Posted 17 November 2025, 7:53 am EST
Hello,
After migrating our WinForms application to .NET 8 (from net 4.8) and upgrading to the latest ComponentOne WinForms assemblies, we are encountering a runtime error related to the legacy C1List control.
Here is the exception we receive when opening any form that contains a C1List:
System.InvalidCastException: Unable to cast object of type 'C1.Win.List.Split' to type 'C1.Win.List.ListBoxView'.
at C1.Win.List.C1List.OnHandleCreated(EventArgs e)
at System.Windows.Forms.Control.WmCreate(Message& m)
at System.Windows.Forms.Control.WndProc(Message& m)
at C1.Win.List.ListBase.Frame.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(HWND hWnd, MessageId msg, WPARAM wparam, LPARAM lparam)This issue appears immediately during control initialization (HandleCreated), before any of our own code is executed.
What we have already tested:
1. All ComponentOne assemblies (C1.Win.*) are on the same version.
2. A clean rebuild of the project.
3. Re-adding the references manually from the ComponentOne installation folder.
Could you confirm whether this casting error (Split → ListBoxView) is a known issue in the latest release?
