Qt ActiveX: threw an exception of type 'System.Invalid.CastException'

[cbries]

Hello everyone,

I have created an ActiveX standalone server with Qt's activex support. So far, the activex server has been registered in the registry, the COM interface can be queries, BUT after creating a new activex server class instance a "System.InvalidCastException" rises.

I like to use the Qt ActiveX component within a C# .Net Application for Windows 7.

• reference to the manually created interop reference has been added to VisualStudio
• the using statement has been added
• the interface and classes are accessible and it seems the class can be instantiated

The simple testing application is:
@
using TcHmiCreatorLib;

namespace WindowsFormsApplication1
{
static class Program
{
[STAThread]
static void Main()
{
ITcHmiAxServer tchmi = new TcHmiAxServerClass();
if (tchmi != null)
{
Trace.WriteLine("Server interface ok");
}
}
}
}
@

Outputs:
@
...
The thread '<Thread Ended>' (0x9d8) has exited with code 0 (0x0).
The thread '<Thread Ended>' (0x1bc0) has exited with code 0 (0x0).
Server interface ok
...
@

But with the Debugger I get the following values:
@

• [TcHmiCreatorLib.TcHmiAxServerClass] {TcHmiCreatorLib.TcHmiAxServerClass} TcHmiCreatorLib.TcHmiAxServerClass

• acceptDrops '((TcHmiCreatorLib.TcHmiAxServerClass)(tchmi)).acceptDrops' threw an exception of type 'System.InvalidCastException' bool {System.InvalidCastException}
• accessibleDescription '((TcHmiCreatorLib.TcHmiAxServerClass)(tchmi)).accessibleDescription' threw an exception of type 'System.InvalidCastException' string {System.InvalidCastException}
• accessibleName '((TcHmiCreatorLib.TcHmiAxServerClass)(tchmi)).accessibleName' threw an exception of type 'System.InvalidCastException' string {System.InvalidCastException}
• autoFillBackground '((TcHmiCreatorLib.TcHmiAxServerClass)(tchmi)).autoFillBackground' threw an exception of type 'System.InvalidCastException' bool {System.InvalidCastException}
• cursor '((TcHmiCreatorLib.TcHmiAxServerClass)(tchmi)).cursor' threw an exception of type 'System.InvalidCastException' TcHmiCreatorLib.MousePointer {System.InvalidCastException}
• enabled '((TcHmiCreatorLib.TcHmiAxServerClass)(tchmi)).enabled' threw an exception of type 'System.InvalidCastException' bool {System.InvalidCastException}
• FocusPolicy '((TcHmiCreatorLib.TcHmiAxServerClass)(tchmi)).FocusPolicy' threw an exception of type 'System.InvalidCastException' TcHmiCreatorLib.FocusPolicy {System.InvalidCastException}
• font '((TcHmiCreatorLib.TcHmiAxServerClass)(tchmi)).font' threw an exception of type 'System.InvalidCastException' stdole.IFontDisp {System.InvalidCastException}
  ..
  ..
  ..
  etc.
  @

Any idea how to fix this?