Combobox selecteditem null. Commented Sep 17, 2012 at 20:00.

• Combobox selecteditem null the comboBox doesn't know what is the value of your custom class ComboboxItem, so either do:. If the ComboBox tries to set the OldValue, the binding system ignores it because the new value matches Why is my ComboBox SelectedItem null? 9. DBNull' cannot be converted to type 'State'. Status. <ComboBox ItemsSource="{Binding Sites, Mode=OneWay}" SelectedItem="{x:Bind ViewModel. The item in the combo box. The SelectedValuePath property is initialized after the SelectedValue property. But this won't fix your issue completely. SelectedItem is null If they are different comboboxes. Stack Overflow. it deselects the currently selected item and blanks the combo. public void BindComboBoxes() { this. IsNullorEmpty combobox. Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company The List contains null value to represent an empty option. Values displayed in debugger's viewer are correct, . Fundamentally, this appears to be caused by your choice to use null as one of the selectable values. BaseView, Mode=OneWay}" The SelectedItem needs to be the same type of the ItemsSource. Thanks. wpf combobox selected item. SelectedIndex is appropriate also. Workarround is to clear the binding before this occurs, and reset it when coming back. I don't As @Mike Eason and @kubakista said, you need set Mode explicitly. In c# null. To clear the selection set the SelectedIndex not the SelectedItem. I have a form, and want to check if the user filled it in correctly. I can set SelectedValue to all kinds of values or types that don't make sense, but I can't set it to null. I have a ComboBox that I populate from a list. Hot Network Questions Cherenkov radiation in the frame of a moving observer Is it bad to ask for accommodations for disability when PhD supervisor might be in bereavement? Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company Visit the blog bind your "Select" button's IsEnabled property to the SelectedItem of the combo-box using a converter that outputs True if the SelectedItem is not null and False otherwise; and maybe also define a trigger in the combo box to display a warning when the SelectedItem is null (use same type converter to set trigger) You might implement the type Validating within the SelectionChanged event handler allows you to cancel your logic if the selection is invalid, but I don't know of an easy way to cancel the event or item selection. , debug/release). ValueMember to "Value". SelectedItem = null; Combobox. For example, in the drop-down box labelled "What is your favourite primary colour?" InvalidOperationException:'System. Populate combobox based on selection of another combobox - Powershell. Through my searches, I've seen where I can simply change the SelectedItem value to -1, and that should load the comboBox on a null choice, but when I use this code I see no difference. Viewed 144 times 1 I am writing a Directory explorer using the MVVM-Pattern. As soon as I let out (click the button) the SelectedItem, vacant space, of the combobox, it becomes occupied and at that point I renew the NewObject Output is : null. Result: Correctly selects the item when the field is created; Loses the item when the field is removed from the display and then added back. SelectedValue will be the ProductID of that row. Follow answered Apr 4, 2016 at 15:18. WPF MVVM Editable Combobox new value is null. These methods are used during the creation and play back of data verification points. SelectedItem property to get the item that's selected. SelectedItem; Share. Expected value : Politician Please someone suggest on this. 15. WPF ComboBox SelectedItem dynamic binding. Top achievements. I'm trying to set the SelectedItem in a ComboBox but without any success. Modified 5 years, 4 months ago. All of my combo-boxes are databound, i. ToString) The . If the handle has not yet been created, The problem is that, when the view containing the ComboBox gets unloaded, the ComboBox's ItemsSource gets nulled, which triggers it to clear its SelectedItem/Text properties, which are for some reason still bound to my viewmodel--thus clearing the data it stores. Reload to refresh your session. It prints barcodes as well. You should remove all references to other projects in your solution and re-add them as project references. wpf default comboBox item when data-binding. By doing that I used combobox. Name is a string, not an EmployeeStatusModel. Controls. How to set an item as selected How To bind ListView values depends on combobox selected item? 64. Combo box item not initally selected. There is no null item of course. The SelectedItem is binded to a property of "City" type. 8. SelectedItem property of a ComboBox in C# can get or set the currently selected item in a ComboBox. Everything works except the situation when the empty option is picked in the combobox. The Selected property is a zero-based array that contains the selected state of each item in a combo box. In our application we have several comboboxes and behavior of specific one is not fine for our automation tests (Teststack. In your code, your SelectedComboBoxOption is a string, but the SelectedItem is a ComboBoxItem object. Improve this answer. However, my ItemsSource is already in the XAML after the SelectedItem, which is what normally sorts this out. ComboBox. If your combo box options coming from dynamic data (DB or Array) then on the backend side you need to set selected value like this: Why is my ComboBox SelectedItem null? 1. SelectedItem will throw a null reference exception with this at the top of the Your problem is IsNothing(cmbReplcmnt. Jeremy asked on 06 Sep 2017, 10:41 PM. Combobox returns null when value is typed. SelectedItem; MessageBox. So say you've bound a list to a collection of Category objects (with each Category object having Name and ID properties). I would like to bind the SelectedItem of the ComboBox to the property specified in the CustomObject, however SelectedItem="{Binding Path=CustomSettingProperty}" is not I'm having some difficulties with null and a ComboBox in WPF/C#; If a add a null item it is not shown/listed in the ComboBox. SelectedItem does indeed have the object I added to the list. SelectedItem value of combo box gets empty on updating from viewmodel in wpf. NET, and WPF. cmbOrganizacionaJedinica. cs: using System; using System. Tried all the solutions for similar issues around here, still no go. WPF combobox selected item. net. The Exception only occurs if the ComboBox is actually part of a Form. But like I said, this go around I want to use the SelectedItem property. I am creating a UI using PowerShell forms. When the control is initialized, if the SelectedItem is Nothing then the default selection will be blank, but as soon as ComboBoxEdit cannot find it in the source and resets selection. First you need to set SelectedItem instead of SelectedValue. 4. Windows will allows you to change the visibility of the object. null, of course, has special meaning, for C#, . SelectedItem); since you remove the selectedItem from the ItemSource which automatically set the SelectedItem to be null. Bind the ItemsSource and SelectedItem properties of the ComboBox to properties in your ViewModel: <ComboBox ItemsSource="{Binding MyItems}" SelectedItem="{Binding MySelectedItem}"/> In MainViewModel. ViewModel and MainPage. That was the NullReferenceException :( Anyway thank you for your help! – TorbenJ. Hot Network Questions Why does it take so long to stop the rotor of a helicopter after landing? Why aren't we bumping into objects outside of the visible range? How is という used in this sentence? Is it appropriate to reach out to executives and/or engineers at a company to express interest in a position? How to set combobox by default to no selected item. wpf combo box SelectedValue = null issue. ASP &lt; But in the process of that the SelectedItem becomes null which isn't really what the user wanted, it's an event due to the UI lifecycle. private void btnRunReport_Click(object sender, EventArgs e) { EmployeeTimecardReport rptEmpTimecard = new EmployeeTimecardReport(); rptEmpTimecard. Whose Selected Value is bound Twoway to another entity's property. Selecteditem on combobox null reference exception. not go on to try to evaluated the ToString() method call. Lease object's SpaceId is bound to the Id of selected Space of VacantSpaces. SelectedItem != null) { MessageBox. Simple application for print labels on a Zebra printer. its should be like : ListItem li = Combox1. Modified 9 years ago. On debugging the selectedvalue is shown to be null despite assigning it a value. 7. Content. Their names can be a bit confusing :). First(); The problem is that I want to fill a ComboBox with an anonymous type result like: This while the answers collections count is 2. If the DataContext is not set, then initially this will be null. A file reference is not updated automatically on build or when you change the build type (e. What is happening is that I have the a view with the combobox on it with data already loaded then an event is fired that updates the data feeding into the ComboBox. POWERSHELL: Can't get 2nd DropDownBox choice passed as variable. Modified 12 years, 7 months ago. From MSDN: When SelectionMode is Multiple or Extended, use the SelectedItems property to get the items that are selected. I have a ComboBox that should work for selection of existing items and/or for adding new ones. Basically you should create a list of options (or objects representing options) and set them as ItemsSource, this way your SelectedItem will be exactly the option which is selected, not the automatically created wrapping ComboboxItem. its easier to use Combobox. You can call CreateControl() in the Form's Constructor to force the creation of the control's handle. SelectedItem can be set, but . SelectedItem = log. ToString(); //<--- this returns null } is this possible? I'm trying not This while the answers collections count is 2. XAML no way of testing this at the moment but you could try to use DynamicObject as a baseclass for your NullPlaceholder. SelectedItem is still null. Visible: Display the element. SelectedViewConfiguration. Value in the Default property of the automatic form text input for those columns and there it did work. Viewed 3k times 0 I want to use SelectedItem to set selection to a combobox from code. SelectedItem if you using a DataSource, this is the item seleted in the datasource. SelectedItem プロパティは、ComboBox で現在選択されているアイテムを取得または設定できます。 ComboBox の選択された値は、最初は null であり、ユーザーが SelectedItem プロパティをオブジェクトに設定した後にのみ割り当てられま Selecteditem on combobox null reference exception. Item again, only the ComboBox that has been bound via XAML will By default, WPF compares the SelectedItem by reference, not by value. public object? SelectedItem { get; set; } The object that is the currently selected item or null if there is no currently selected item. check combobox. Setting new index raises the SelectedIndexChanged event I'm try to this : 1. I can only get it to work by using SelectedValue. This will work when setting the visual part of the ComboBox, but when I do this: long nbr = Convert. WPF form has ComboBox where null value associated text "-- Please select --". cboTypes. That means if the SelectedItem isn't the exact same object in memory as the item in your ItemsSource, then the comparisom will return false and the item will not get selected. Ask Question Asked 9 years ago. Text = "2010"; For getting the value after a change, though, and maybe it's because I didn't set SelectedValuePath="Content" everywhere, or maybe because I didn't use SelectedValue to set it (and why I'm mentioning it), it becomes slightly more complicated to determine the actual MVVM solution:. SelectionChangeCommitted I want to make a ComboBox in WPF that has one null item on the top, when this gets selected, the SelectedItem should be set to null (reset to default state). In my case I typically do that in the constructor of A ComboBox is bound to a BindingList<T> instance as a data source, the DisplayMember and ValueMember properties are set and working as supposed. GetUsers()); The list actually shows correctly, but the selectedItem (which is something that i get from the viewmodel) gets reset and i can't set it again from code-behind. But, as soon as I make the call to ShowDialog, the Update: Sample source code demonstrating this technique can be downloaded here: WpfNullableComboBox. You switched accounts on another tab or window. At this point the ComboBox thinks SelectedItem is null, but the Source thinks it's OldValue. For example, var tmp = Selected; Selected = null; Items. At this point, a NullReferenceException is thrown. SelectedItem: Gets or sets currently selected item in the ComboBox. I tryed ComboBox1. why combobox SelectedValued Throw exception when there is nothing Seleceted. I'll try to look into it here to see if I can find anything. 0 I am trying to set Combobox Selected Item property to null through Control Template I've added Checkbox so I can use datatrigger and set SelectedItem to null when Checkbox isChecked is true. When the control is initialized, if the SelectedItem is Nothing then the default selection will be blank, but as soon as you choose an item in the combo box, you can not reselect the anonymous user-3316, I didn't post all code. 867+00:00. 13. 4. However, the selected item has changed to the item I want it to be. Dictionary<Control, string> controls = new Dictionary<Control, string>(); Binding code (Sorin Comanescu's solution - worked like a charm): Requirement. Martin asked on 29 Jul 2015, 02:17 PM. I needed it at work and couldn't find any good options. Add a comment | -1 In How to clear combo box contents in vb. So the datasource isn't null Very strenge huh? Solution: The SelectedValue, SelectedIndex, SelectedItem properties can't be set until the control is added to the form. Something like this: public class NullPlaceholder : DynamicObject { public string DisplayString { get; set; } public override bool TryGetMember(GetMemberBinder binder, out object result) { return DisplayString; } /// <summary> /// This is here so that if you don't define a I'm unable to run your test project because of the version, but I copied the ViewModel class and XAML to a new test project and it all seems to work as expected, with the selected item being cleared, combobox disabling, and watermark appearing when the button is clicked. The DataGridView shows data when the DateTimePicker and the class are used. MyCollection = new ObservableCollection<User>(DAL. I want to have ComboBox where user may enter some text or choose text from drop-down list. Viewed 564 times In this case comboFilter. This is the class: public static bool IsMarkAttend Object binding to Winforms ComboBox fails when SelectedItem is null. Лабораторна Робота № 3 ComboBoxにおいて表示名と値を関連付ける SelectedIndex = 0; comboBox1_SelectedIndexChanged (null, null);} private void comboBox1_SelectedIndexChanged (object sender, EventArgs e) {// labelに現 You signed in with another tab or window. I decided to use Avalonia to build cross-platform application (Windows, Linux). each combo-box is populated using a datasource. Object selectedItem = comboBox1. Category is just an object with a Name and Id. I have noticed that sometimes my Reset method works, i. Show("Selected Item Text: " + selectedItem. State property? Checking SelectedItem by code-behind results with null. 0. I should have made it clearer the combo box is actually cboType so I am using cboType. ItemsSource is set to a List<DvcTypes> in code:. Combo Box, DropDown all are having the same logic to clear/remove all items from them and it is like below. I had a . My combobox Here is what I've been using, I hope it Helps: ComboBoxAdaptor. Set them by using ItemsSource. This appears to be the problem: SelectedItem="{Binding Path=Id}" If the "Id" property in the DataContext is not an item in the ItemsSource, SelectedItem will be set to null. SelectedItem rather than SelectedValue. It will be The other combobox then reads out the selected items of cmbGroup and applies some data of the selected item to itself. a, b, or c) in Items, and then delete the text. ; The Selector Part (i. but thanks for 拡張メソッドとリフレクションを使用して、なんとか動作させることができました。私はまだより良い解決策を見つけたいと思っていますが、それはうまく機能しています。 As briefly mentioned before, the ItemsTemplate that we might apply to the ComboBox will not affect how the NULL item is visually represented in the dropdown. It's not that SelectedValue can not be null. You don't want to assume that there will always be a value in SelectedItem. DBNull before trying to assign it to the Address. As you can see in the above screenshot it shows the first record from the Product list. If SelectedItem is null, then the entire expression will "short-circuit", i. Further, if the SelectedItem is null, the approach I provided won't The problem of getting SelectionChanged events to fire on DataGridComboBoxColumn cells was one that plagued me recently. ValueMember = "Id"; cmbOrganizacionaJedinica. Here's a summary: The SelectedItem property returns the entire object that your list is bound to. SelectedItem != null But when I'm getting the value of it returns null. You are getting NullReferenceExeption because of you are using the cmb. SelectedValue it crashes. thanks. I have an ASPxComboBox which I was able to get filtering correctly on user input. excellent. SelectedValuethe ValueMember of the Datasource or the currently selected value if you added your own Items I would rather have the . You can get or set the combo box's selected item by using the SelectedItem property, SelectedItem = null; SelectedValue = null; SelectedIndex = -1; In SDK 17763 and later, the value of the SelectedItem property (and therefore, SelectedValue and SelectedIndex) is not required to be in the combo box's Items collection. False: We would like to show you a description here but the site won’t allow us. WPF ComboBox performance problems by binding a large collections. I am using WinForms and MySQL in my project. Poor naming on microsoft's part. Thanks in advance! Also includes the code for the initial load of cboCountries combo box. Modified 7 years, 8 months ago. 5 Answers 1246 Views. When the control is initialized, if the SelectedItem is Nothing then the default selection will be blank, but as soon as you choose an item in the combo box, you can not reselect the I think you should be checking combobox1. However i faced an issue when component (ComboBox) source IList / IObservableCollection is updated i can't update combobox content. You signed out in another tab or window. selectedItem or . However, after setting the MainPage. Ask Question Asked 7 years, 8 months ago. SelectedValue to null cause a ArgumentNullException? 0. Rank 1. When InitializeComponent is called, it parses the XAML which sets the SelectedItem binding. Employee = GrpEmpCBox. Reset Text in ComboBox. ItemsSource = new BindingSource(CommonMgr. Item again, only the ComboBox that has been bound via XAML will show the correct corresponding content for its SelectedItem. Ask Question Asked 12 years, 7 months ago. In fact, its value is null at the time I'm trying to Combox1. List<string> numbers = new List<string>(); for (int i Interesting problem. You have to write some ItemsSource that does not contain a reference to the same object in memory as the current SelectedItem; Actually I want to bind Combobox in Datagrid templete, Combobox collection exist in view model, When I change first column property other rows combo box item became null. SelectedItem = null; Share. In this case, you should be able to simply use . Position = iDataSourceItemIndex; // Create and bind the combobox to its datasource, with implicit selected index ComboBox comboBox1 = new ComboBox I got a combo box in wpf form I set the ItemSource to the collection of Dictionary of (Pet Type) and just display the Value and hid the Key. SelectedValue. I've avoided using SelectedValue and SelectedItem in the same ComboBox ever since. As soon as I let out (click the button) the SelectedItem, vacant space, of the combobox, it becomes occupied and at that point I renew the NewObject I am a bit frustrated with combobox right now and am hoping someone has an answer for my question. 3 Answers 794 Views. Combobox SelectedItem Becomes Null. sort of like the way, some text boxes contain gray text such as "enter user name" Why does setting the SelectedValue of a ComboBox to null cause an ArgumentNullException?. If possible I would want it to do it only with XAML code or an attached behaviour, because I don't really like changing stuff in the We would like to show you a description here but the site won’t allow us. And then data bound only these two properties to a ComboBox: <ComboBox ItemsSource="{Binding SalesPeriods}" SelectedItem="{Binding SelectedItem}" /> That's it that's all you need for a perfectly working example. Binding source should be updated when user press Enter after typing or when item is simply selected from drop-down list (best View behavior in my case). RemoveSelected() method use a temp value and set the selected item to null before removing the previously selected item. // Use a binding source instance before adding your datasource to the combobox BindingSource bindingSource = new BindingSource(dataSource, null); // The item selection occurs here! bindingSource. SelectedValuePath = "Key"; } C# の ComboBox の ComboBox. Once I have added the list to the ComboBox's items, I try to set the selected item to one of the items from the list. user14743092 user14743092. SelectedItem; or . cs: public ObservableCollection<string> MyItems { get; set; } private string _mySelectedItem; public Update: Sample source code demonstrating this technique can be downloaded here: WpfNullableComboBox. How do I indicate that a combo box has been populated with a selection? Hot How To bind ListView values depends on combobox selected item? 64. Basically Im trying to add clear filter checkbox that will show up when SelectedItem has some value, and upon clicking this checkbox selected item will I'm not actually using ComboBox as the variable name. SelectedContractSite, Mode=TwoWay}"/> But when I change to the following xaml, the ComboBox contains the sites, but does not show the SelectedItem as the default. How to add a void item into a ComboBox, so that at first load user would see an empty string. – kakkarot. Developer Express Inc disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. UWP Combobox SelectedItem ignores its bound value. I used the following solution: combox. Sarah 186 Reputation points. I do something alike outside of a loop, and for a combobox not created in code, and it works there. And at least in my experience I've found that having both the SelectedValue property and the SelectedItem property assigned in a ComboBox was a sure way of messing things up. Why does setting ComboBox. DataTrigger when SelectedItem is null to select the first item in the list. The list is an ObservableCollection of the same type as the selectedItem. C# - Databound Combobox always returns null value for . Binding a String to SelectedItem won't change ComboBox's selected item. ReplacementTo = If(IsNothing(cmbReplcmnt. Skip to main content. Suppose we have a DataSource bind to a collection from Database. SelectedItem; string selectedText = cbi. SelectionChangeCommitted. This gives meaning because such a template Now, we need to make sure that the ContentPresenter used in the selection box gets this template if the SelectedItem property is NULL. If you want to retrieve the value of the combobox after it is changed, you can use the When I look with breakpoints there is a value in opstapplaats. cboType. To change this behavior you can do the following: Enable caching in your tab control so that controls aren't Even after data is saved PropertyChanged gets called but when I check Combobox SelectedItem in SelectionChanged Event handler it is null. ToString so that you have an idea of what was selected or if nothing was selected at all. Clear(); //For I have a combo box in which I have to display the dates from a database. After the control is added to the form, the selectedValue, -Index and -Item properties can be set. xaml; windows-phone-8; (State)ComboBox. ToString(); } } If you use ComboBox with binding data, like ComboBox Selected Item gets null. SelectedValue which is null. comboBox. Items. ToString() right after the creation of Form1. Initially the SelectedItem is null, and thus the Combobox display is blank. ToString()); } Share. So the binding fails because the type of the binding doesn't match the target property. The property binded to SelectedItem is not updated with the null value but keeps the previous selection. My solution was to sub-class the WPF combo-box and add an internal handler for the SelectionChanged event. Only the selected item part works. SelectedItem), "", cmbReplcmnt. Clearing items in Combobox if user selection changed. At some point of the code I am to switch the selected value programmatically given a ValueMember value and this works perfectly in a perfect case done simple as just comboBox. Collections; using System. locatie_id (the correct one), but SelectedValue stays null. Jeremy. Follow answered Mar 23, 2021 at 11:13. Collapsed: Do not display the element, and do not reserve space for it in layout. StopEventVariable; After assign, stopEventCombobox. When the combo box loses focus, the selection point moves to the beginning of the text and any selected text becomes unselected. comboBox1. GetPetTypesDropDown(false), null); this. Now when you load your edit screen, it will have bound the list to the combobox and display the variable you set. The second combobox (ddlProduct) is not databinded because i do not use a single table, i The correct value to check here is the SelectedItem property. Text() to set it:. My UI consists of a ComboBox which contains a path to a directory and a TreeView which acts as a Directory explorer. A solution is to set the ItemsSource of the combobox to the list (example: "DeviceNameList") and set the SelectedItem of this combobox to a variable that matches the type of elements inside your list (SelectedDeviceName). The SelectedItem property in the viewModel is actually properly set, but it doesn't get to the UI. The "option" ComboBox contains three values: City State Country Wh no way of testing this at the moment but you could try to use DynamicObject as a baseclass for your NullPlaceholder. Viewed 510 times 1 I have set GenericCollection of an entity with it's ID property set to 0 initially and set a combobox Itemsource to this generic collection. If Source raises a PropertyChanged event realizing this desync has happened, the binding system ignores it because the value on Source hasn't changed. I would also use a List<string>:. C# ComboBox. Isn't it? How to create combobox control with non-selectable items? For example, such groupnames or categorynames which visually divide items in dropdownlist into some groups or categories. C# Winforms - setting combobox selected value. Ask Question Asked 5 years, 4 months ago. For starters, your combobox ItemSource is bound to a property called Categories but you do not show how this property is coded or how your NodeCategory property is initially synced with the item. The below is a minimal sample code for this answer. Extract Combo Box text via confirmation button. Ask Question Asked 3 years, 6 months ago. ToString(); MessageBox. SelectedValue throws null reference exception. The IBM® DevOps Test UI (Test UI) framework calls the getTestDataTypes() and getTestData(String) proxy methods for extracting data from controls for verification and reference. cmbDDLFilter. (ComboBoxItem)(sender as ComboBox). I want to enable/disable a ComboBox based on if there is an item selected in another ComboBox. How could i solve this out? The ComboBox is part of a form which is bound to a CustomObject class, and one of the properties on that class is a CustomSettingProperty. Commented Jan 7, 2016 at 8:52. SelectedIndex the index of the selected value. SelectedItem is not ComboBoxItem. eg. Item properties to null, and then settingMainPage. do something But if combobox not selected, switch-case is return null exception I solved this with try-catch but i'm . Generic; using System ComboBox selecteditem dataitem null. Disclaimer: The information provided on DevExpress. Remarks. You should use comboBox. Check for null in comboFilter_SelectionChanged: private void comboFilter_SelectionChanged(object sender I have a situation where I need to style the selected item in a ComboBox differently (make the text bold) when it is one of all except one value. Elements that have a Visibility value of Collapsed do not occupy What you have here is the classic "Project Reference/File Reference" problem. SelectedItem != null){ //Do something } else{ MessageBox. About; (Combobox. I was able to get it working by setting a trigger on the Style, but that overrides my custom global style for the combobox. When SelectionMode is Single, use the Selector. Hidden: Do not display the element, but reserve space for the element in layout. Data. (In fact, it appears to flicker into view and then disappear). To avoid updating DataRole in this scenario, you can set In my application I have a Reset method that sets the SelectedIndex for each combo to -1. ToString) Combobox SelectedItem Becomes Null. Selected. You You can show the Watermark by adding Load event for your ComboBox and adding its code like below when the selection is null: private void myCom_Loaded(object ComboBoxEdit resets its SelectedItem when the ItemsSource property is set to null at the binding level. It'll probably work, but documentation doesn't state that. selectedItem -> 3. Obviously when the RefreshMyItems() method is called the combo box receives the Collection Changed events, updates its items and does not find the SelectedItem in the refreshed collection => sets the SelectedItem to null. Viewed 324 times 0 I have been stuck in this for whole day. I have a C# Avalonia project to communicate any Serial (RS232) devices, currently i am at the beginning of developing this app. Text" field doesn't reflect the currently selected item. For your requirement, you could set the judgment condition to solve this issue. WriteLine anonymous user-3316, I didn't post all code. SelectedItem as DataRowView; SelectedItem is the databound row which created that entry in the combobox. public ObservableCollection<Type> MyList { get; private set; } C# Program Crash comboBox SelectedItem ToString. SelectedValue not. selectedvalue. The After my object(log) stored the value, next time, when I show this user controller, I want combobox can show this value automatically, I try to do it in below code in user controller's constructor, but can't work： stopEventCombobox. - LabelPrint/Form1. ComboBoxItem: Software. 1. 5. You should see that the display of the items comes from the ToString method without your displayPeriod property. I'll try to insert code The ComboBox. when UpdateSourceTrigger=PropertyChange (default) is set, then source update will trigger after I'm not actually using ComboBox as the variable name. In this case, getting the SelectedText property retrieves an empty string, and setting the SelectedText property adds the specified value to the beginning of the text. products where p. I have a Listview that has a checkbox as one of the columns. And when I select a value from Items, it Disclaimer: The information provided on DevExpress. Setting Description; True: The combo box item is selected. SelectedIndex = -1; You can set the SelectedItem or SelectedValue as well, but change it to null instead of -1 (these point to an object not an integer). Hey Aimen! It was a combobox, I figured out a work around, I went and made the fields text fields in the SP list and added comboboxes independent to the form that updates the list. In a WPF ComboBox how can you make a null instance in ItemsSource selectable when using DisplayMemberPath? I am binding to a collection of objects and have added null to that collection. SelectedItem == null. SelectedItem changes from the previously selected item to null. Clear() is called, then rebuilt, and SelectedItem set). I kept getting a null value when using 'SelectedText' or 'SelectedValue' but simply using 'Text' works. I've searched like forever, but didn't find a solution that was satisfying. The first item is represented by a zero (0), the second by a one (1), and so on. How to show TreeView on ComboBox. Combobox binding breaks after button click WPF MVVM. This is with 11. View DotNet_ЛР3_ІПЗ-22-4_Котвіцький. com and affiliated web properties (including the DevExpress Support Center) is provided "as is" without warranty of any kind. . ComboBox twoway binding with XElement. In the form there's a combo box; how can I build the "if" statement for checking whether the user picked an . It gives wrong value. 0. 2015 at 16:47. SelectedValue will be null even though I set the . Unable to assign selected value to In a Combobox, while having its Items property bound to a collection and also having its SelectedItem bound to a string property, selecting the same item twice will update the SelectedItem property's value to null. My combobox was a toolstrip combobox. In addition, I want to be able to have a Therefore as it seems like only the initial selected item is not recognized you can try to apply some refreshing of the RadComboBox. ComboBox SelectedValue doesn't show. The reason why the first combobox works correctly is because i have binded the combobox to the category table, so the DisplayMember = CategoryName and the ValueMember = CategoryID. SelectedItem = (from p in db. In that: when the program is running the above code ddlProduct. C# Combo Box SelectedValue Null. The SelectedItem property is a proper member of the ComboBox control. Ok, my workaround was to change the Customer getter to: <ComboBox SelectedItem="{Binding Carrier, Mode=TwoWay}" ItemsSource="{Binding Carriers}" /> Set IsEditable="True", IsReadOnly="True", and your SelectedItem equal to whatever object you want to hold the selected item <ComboBox ItemsSource="{Binding SomeCollection}" Text="{Binding CurrentValue}" SelectedItem="{Binding SelectedItem}" IsEditable="True" IsReadOnly="True"> And SelectedItem stores the selected item. ToInt64(this. But when I try to get the SelectedItem it is null. Now I want to save the selected item to the database. SelectedValue); The . You can override the getTestDataTypes() method to add more specific data types for a control. I read a lot and found out, that you cannot set SelectedItem of combobox to the item that is not in ItemsSource. Second, you're setting the SelectedItem before the ComboBox has actually been set up, try setting the SelectedItem in the Window's loaded event. Adding the ComboBox's SelectedItems, I get a NullReferenceException. SelectedItem. ObservableCollection<Category>. So the selected item should be an EmployeeStatusModel. But in other cases WPF ComboBox SelectedItem Set to Null on TabControl Switch. Timing. This item is definitely not null. toString(). There is no problem with the rest of code and there exists a state with State_Id=3. The SelectedItem property will return you the currently That's not guaranteed to work when SelectionMode is Single. Any idea why the BindingSource appears to be taking the null SelectedItem and making it System. SelectedItem or Combobox1. Commented Jun 25, 2013 at 17:18. SelectedText is also null, but the . Hopefully, you can Change XAML SelectedIndex to SelectedItem: <ComboBox ItemsSource="{Binding Path=LessonNumbers}" SelectedItem="{Binding SelectedLessonNumber}" /> UPDATE: Somewhere you must set the DataContext of your Window to reference the collection from your XAML. DataSource = vratiOJ(); Debug. SelectedItem retunrs you selected ListItem object not text value of selected item. SelectedValue not working. This means that the cpuCount variable is initialized right after the form is created, thus far before you have the chance to change the selected item with your mouse. Text to get what you are looking for. As several have pointed out, there is nothing selected in the ComboBox when you assign SelectedText to selectedNumber. Windows. string str = comboBox. Either its null before entering into method OR becomes null after this line - comboBox2. //For checkbox list cblTest. This property indicates the zero-based index of the currently selected item in the combo box list. SelectedItem giving Null value. zip By default, combo boxes in WPF have some really annoying behaviour. PowerShell: How do I get information selected in a combo box to be used as a variable later on in? ComboBox. the "drop-down" part): The selected item in this part corresponds to the SelectedItem property. The same effect can be achieved reading the Handle property: . The problem is with SelectedItem. I would try two things: First, don't call AddRange every time through the loop - build the array in the loop and then once the loop exits you can use AddRange. Show(selected); This gives me System. 2022-04-22T23:29:13. The code is setup This means that first time the next object is selected they see null in the combobox but subsequent changes of the object then shows correct property value. My table structure is In my project I have three combo boxes and one TextBox. So the Profession property of Profession1 will be set null. SelectedItem; int selecteVal = I guess your problem is this line: SelectedItem="{x:Bind ViewModel. If I click anywhere but the actual checkbox the SelectedItem of the ListView is set to the current selected row, as expected. I'm pretty new here. Basically Im trying to add clear filter checkbox that will show up when SelectedItem has some value, and upon clicking this checkbox selected item will In the code below, the method called "EditBonus" resets the combobox list be re-reading the file to make sure nothing has changed (Bonuses. The problem also involves the order in which the initialization of the ComboBox element is done. Setting a default selected item in ComboBox in WPF MVVM application. this will also allow you handle the default case where you get back an empty string if the SelectedItem is null. White). The basic intent is to bind the SelectedItem of the ComboBox to the Model so that the Data of the SelectedItem can be modified through other interactions. When i run my app in debugger it will throw a null reference exception if I enter text into the ComboBox that matchs an Item(ie. Selected item in combobox is null - if I scroll in my datagrid or resize the window then the combox selected value value shows up. A ComboBox is a composite control with two of its parts being: The Text Part: the value in the this part corresponds to the Text property of the ComboBox. InvalidOperationException: Must have non-null value for The Visibility under System. The now, after the execution of renewNewObject function, the combobox's SelectedItem becomes null so to remove the null from ComboBox, I've to move CurrentItem manually in Combo's OnItemsChanged: protected MVVM binding cannot be performed correctly when ComboBox Items contain prefix entries. SelectedValue = null. First, VacantSpaces is Space object not Lease and the Lease object has a property, SpaceId. But I would need the combo box to use Equals method to select the correct item in the new collection. Cause. Based on ComboBox. But if the selected item == null then nothing can be read out. Add a comment | 3 Answers Sorted by: Reset to (myxyzcombo. Remove(comboBox2. Forces the creation of the visible control, including the creation of the handle and any visible child controls. Martin. I'm using a RadComboBox and would like to get the selected item that was bound to the combobox instead of the selected value, index or I used Sorin Comanescu's solution, but hit a problem when trying to get the selected value. For example, Items={1,10,100}, SelectValue and SelectedItem equals NULL when Text=10 is assigned, please check this BUG and give a fix, I am trying to create a reusable control for WPF which allows the user to select a null option in addition to all the items in the ItemsSource binding. ComboBox This is a migrated thread and some comments may be shown as answers. SelectedValue = newValue. Or, you could try If I do that I can choose the selected item by doing something like: comboBox1. The value of the Handle property is a Windows HWND. And when I select value from Items, it is set to binding SinParams value. The problem you're having is probably related to the fact that the ". Here is de XAML declaration of my ComboBox <ComboBox ItemsSource="{Binding Path=MyList}" SelectedItem="{Binding Path=Type}" /> MyList is declared as . clear() deletes the items from the list while setting the selected item to null clears the selected data. My Ports list looks like: In a Combobox, while having its Items property bound to a collection and also having its SelectedItem bound to a string property, selecting the same item twice will update the SelectedItem property's value to null. Occurs when the selected item has changed and that change is displayed in the ComboBox. SelectedValue not working as expected. and after manipulating window size a few times. ToString() throws NullReferenceException which means if that value is null means definitely exception will thrown. Collections. cs at We would like to show you a description here but the site won’t allow us. I have tried selectedItem but it doesn't just give me the value it also shows System. Setting ComboBox SelectedValue. ; The image above was taken immediately after I want to enable/disable a ComboBox based on if there is an item selected in another ComboBox. Problem. Winforms Combobox SelectedValue is Null. Whenever the event fires, my private internal handler raises a EmployeeStatuses is an ObservableCollection<EmployeeStatusModel>. Your fixed code should be as follows: classEquipmentItem. Remove(x); also results in the correct behavior without needing to change SelectedItem (which reads correctly to me) to SelectedValue (which In the end, you can't just set the "Visibility" property of the TextBlock to "Hidden" in order for it to be hidden when the combo box's selected item isn't null; you have to SET it that way by default (since you can't check not null in triggers, by using a Setter in XAML at the same place as the Triggers. – Ryan Ward. ComboboxItem selectedCar = (ComboboxItem)comboBox2. The problem is that when you modify the DataContext of combobox, the DataContext is set null first and then turns to Profession2. Setting selected item in C# Combobox. ToString() ); However, after setting the MainPage. show("Please select a item"); } Debugging a strange NullRefException i see the following picture: So when the code is referring to . click button -> 2. So if you want to use SelectedComboBoxOption to get and set When I select a cell with the ComboBox to edit, SelectedItem is null. For example, this will probably not work. How can i solve this issue? If I tab to the ComboBox and try to tab out, the SelectedItem is null, but I get an exception: Object of type 'System. DataRowView in my MessageBox How to set combobox by default to no selected item. Combobox Binding MVVM WPF SelectedValue. Modified 3 years, 6 months ago. 3. When the selected item is null, I would prefer the Combobox to display "Select an item" to guide the user to select something from the combobox. SelectedItem != null) { string strID = By default, combo boxes in WPF have some really annoying behaviour. But value, wich binding to SelectedItem is in the ItemsSource list. Set textbox value based on the combobox selected item. g. The event that is fired on change is ComboBox. (order == null) { Order = new Order(); OrderUserControlTitle = "Nieuwe bestelling toevoegen"; } else { Order = order; SelectedProduct = _productService. The selected value of a ComboBox is null initially and only be assigned after the user sets the Gets or sets currently selected item in the ComboBox. I used the "combobox" property, which exposes a normal combobox. cmbBudgetYear. I'm suspicious that EditEmployeeVM. I cannot understand how . Something like this: public class NullPlaceholder : DynamicObject { public string DisplayString { get; set; } public override bool TryGetMember(GetMemberBinder binder, out object result) { return DisplayString; } /// <summary> /// This is here so that if you don't define a Based on the selected item id, recover the object on the itemsource collection and set the selected item property to with it. So I would guess that either something in your environment is affecting it, or it is Can anyone tell me how to get the selected item of a ComboBox to a string variable? string selected = cmbbox. GetProductById(Order In your case either Combobox. 852 1 1 gold badge 6 6 silver It might be helpful to take a closer look at how the ComboBox and it's related properties function. Commented Sep 17, 2012 at 20:00. DisplayMember = "Naziv"; cmbOrganizacionaJedinica. Why do you use a Try setting the initial value of SelectedCountry to null, or use this binding: SelectedItem="{Binding SelectedCountry, Mode=OneWayToSource}" It seems that the combobox looses the selected item in VisibilityChanged event. SelectedItem; ComboBoxItem cbi = (ComboBoxItem)MyCombobox1. If, on the other hand I click onto the checkbox (without clicking on the row first) then the SelectedItem is null or the previously clicked row. Text. Mohit Shah Mohit Shah. Try setting the initial value of SelectedCountry to null, or use this binding: SelectedItem="{Binding SelectedCountry, Mode=OneWayToSource}" Please sign in to rate this answer. You can set It. ProductId = 5 select p). SelectedEmployee. SelectedItem is null. I have also bound SelectedItem to property. e. Show(myxyzcombo. The programmatically bound combo box does not show any content for its SelectedItem. items. 2. When selecting values that are not null, my SelectedItem property changes correctly. Also you can use the UISpy tool to check if private void MyCombobox2_SelectionChanged(object sender, SelectionChangedEventArgs e) { if (MyCombobox2. DisplayMemberPath = "Value"; this. selectedValue Hot Network Questions How to Create Rounded Gears with Adjustable Wave Angles From what I can see, you are calling form. I am trying to set Combobox Selected Item property to null through Control Template I've added Checkbox so I can use datatrigger and set SelectedItem to null when Checkbox isChecked is true. ToString can't be evaluated in the case where the SelectedItem is Nothing so the IsNothing function fails. Try using the following code and you will see that the selected item is kept in sync as the user changes the value in the combobox. DataRowView row = combobox1. Later when DataContext is The ComboBox control inherits from the ListControl control. SelectedItem != null. pdf from FICT 121 at Zhytomyr State Technological University. I notice though that the . ComboBox's . You shouldn't insert the combobox items manually. We would like to show you a description here but the site won’t allow us. uxkc jdkey jphaf hcciit bbmppj orsbbk jidjct gxi unsm zdd