Error adding Items of ComboBox in DemoConsole application

[Nora-Zhou01]

.NET version

.NET 8.0.100-preview.7.23330.16

Did it work in .NET Framework?

Yes

Did it work in any of the earlier releases of .NET Core or .NET 5+?

It also repro's in .NET 7.0.

Issue description

In Winforms repo, there has a DemoConsole test app, System.InvalidCastException: 'Unable to cast object of type 'Entry' to type 'System.String'.' Occurs after adding an item of ComboBox in a DemoConsole application.

combobox.mp4

Call Stack:

System.InvalidCastException
HResult=0x80004002
Message=Unable to cast object of type 'Entry' to type 'System.String'.
Source=System.Windows.Forms.Design
StackTrace:
at System.Windows.Forms.Design.StringCollectionEditor.StringCollectionForm.OKButton_click(Object sender, EventArgs e) in C:\Users\xx\winforms\src\System.Windows.Forms.Design\src\System\Windows\Forms\Design\StringCollectionEditor.StringCollectionForm.cs:line 158
at System.Windows.Forms.Control.OnClick(EventArgs e) in C:\Users\xx\winforms\src\System.Windows.Forms\src\System\Windows\Forms\Control.cs:line 7729
at System.Windows.Forms.ButtonBase.OnClick(EventArgs e) in C:\Users\xx\winforms\src\System.Windows.Forms\src\System\Windows\Forms\ButtonBase.cs:line 889
at System.Windows.Forms.Button.OnClick(EventArgs e) in C:\Users\xx\winforms\src\System.Windows.Forms\src\System\Windows\Forms\Button.cs:line 249
at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent) in C:\Users\xx\winforms\src\System.Windows.Forms\src\System\Windows\Forms\Button.cs:line 276
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks) in C:\Users\xx\winforms\src\System.Windows.Forms\src\System\Windows\Forms\Control.cs:line 12347
at System.Windows.Forms.Control.WndProc(Message& m) in C:\Users\xx\winforms\src\System.Windows.Forms\src\System\Windows\Forms\Control.cs:line 13122
at System.Windows.Forms.ButtonBase.WndProc(Message& m) in C:\Users\xx\winforms\src\System.Windows.Forms\src\System\Windows\Forms\ButtonBase.cs:line 1466
at System.Windows.Forms.Button.WndProc(Message& m) in C:\Users\xx\winforms\src\System.Windows.Forms\src\System\Windows\Forms\Button.cs:line 375
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m) in C:\Users\xx\winforms\src\System.Windows.Forms\src\System\Windows\Forms\Control.ControlNativeWindow.cs:line 64
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) in C:\Users\xx\winforms\src\System.Windows.Forms\src\System\Windows\Forms\Control.ControlNativeWindow.cs:line 113
at System.Windows.Forms.NativeWindow.Callback(HWND hWnd, MessageId msg, WPARAM wparam, LPARAM lparam) in C:\Users\xx\winforms\src\System.Windows.Forms\src\System\Windows\Forms\NativeWindow.cs:line 373
at Windows.Win32.PInvoke.DispatchMessage(MSG* lpMsg)
at System.Windows.Forms.Application.ComponentManager.Microsoft.Office.IMsoComponentManager.FPushMessageLoop(UIntPtr dwComponentID, msoloop uReason, Void* pvLoopData) in C:\Users\xx\winforms\src\System.Windows.Forms\src\System\Windows\Forms\Application.ComponentManager.cs:line 291
at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(msoloop reason, ApplicationContext context) in C:\Users\xx\winforms\src\System.Windows.Forms\src\System\Windows\Forms\Application.ThreadContext.cs:line 1069
at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(msoloop reason, ApplicationContext context) in C:\Users\xx\winforms\src\System.Windows.Forms\src\System\Windows\Forms\Application.ThreadContext.cs:line 935
at System.Windows.Forms.Application.RunDialog(Form form) in C:\Users\xx\winforms\src\System.Windows.Forms\src\System\Windows\Forms\Application.cs:line 1176
at System.Windows.Forms.Form.ShowDialog(IWin32Window owner) in C:\Users\xx\winforms\src\System.Windows.Forms\src\System\Windows\Forms\Form.cs:line 5381
at System.Windows.Forms.Design.EditorServiceContext.System.Windows.Forms.Design.IWindowsFormsEditorService.ShowDialog(Form dialog) in C:\Users\xx\winforms\src\System.Windows.Forms.Design\src\System\Windows\Forms\Design\EditorServiceContext.cs:line 163
at System.ComponentModel.Design.CollectionEditor.CollectionForm.ShowEditorDialog(IWindowsFormsEditorService edSvc) in C:\Users\xx\winforms\src\System.Windows.Forms.Design\src\System\ComponentModel\Design\CollectionEditor.CollectionForm.cs:line 186
at System.ComponentModel.Design.CollectionEditor.EditValue(ITypeDescriptorContext context, IServiceProvider provider, Object value) in C:\Users\xx\winforms\src\System.Windows.Forms.Design\src\System\ComponentModel\Design\CollectionEditor.cs:line 251
at System.Windows.Forms.Design.ListControlStringCollectionEditor.EditValue(ITypeDescriptorContext context, IServiceProvider provider, Object value) in C:\Users\xx\winforms\src\System.Windows.Forms.Design\src\System\Windows\Forms\Design\ListControlStringCollectionEditor.cs:line 31
at System.Windows.Forms.Design.EditorServiceContext.EditValue(ComponentDesigner designer, Object objectToChange, String propName) in C:\Users\xx\winforms\src\System.Windows.Forms.Design\src\System\Windows\Forms\Design\EditorServiceContext.cs:line 61
at System.Windows.Forms.Design.ListControlUnboundActionList.InvokeItemsDialog() in C:\Users\xx\winforms\src\System.Windows.Forms.Design\src\System\Windows\Forms\Design\ListControlUnboundActionList.cs:line 21
at System.Reflection.MethodInvoker.Invoke(Object obj, IntPtr* args, BindingFlags invokeAttr)

Steps to reproduce

Test sample: DemoConsole in Winforms repo

[elachlan]

@Nora-Zhou01 can you please test the fix in #9419?

[Nora-Zhou01]

@elachlan Now there is no error in adding the item in ComboBox, but after adding the item and opening it again, it is empty, is this expected?

9420.mp4

[elachlan]

I believe that's being tracked in #9389? Please correct me if I am wrong.

[elachlan]

The issue is here:

winforms/src/System.Windows.Forms.Design/src/System/Windows/Forms/Design/StringCollectionEditor.StringCollectionForm.cs

Lines 193 to 211 in 918e346

	protected override void OnEditValueChanged()
	{
	object[] items = Items;
	string text = string.Empty;
	for (int i = 0; i < items.Length; i++)
	{
	if (items[i] is string)
	{
	text += (string)items[i];
	if (i != items.Length - 1)
	{
	text += "\r\n";
	}
	}
	}
	_textEntry.Text = text;
	}

It is assuming the items are a string. So we need to convert it to use ToString() like the other parts of the code. I'll add a fix later today.

[Nora-Zhou01]

Verified this on latest .NET 8.0.100-preview.7.23362.29, issue was fixed, item is displayed again after adding an item to ComboBox in DemoConsole application.

9420.mp4

[Philip-Wang01]

Verified this issue on winforms repo with DemoConsole test app from release/8.0-preview7 branch, it was fixed. Test result is same as above.