问题
I'm in charge of the maintenance of a C# application (VS 2005). This C# applications calls a dll ("mydll.dll"). I needed to make a few changes on the dll in question.
I have the file "mydll.vbp" that was written in Visual Basic 6.0. I made my changes in Visual Studio and, then, "made "mydll"" from the Visual Basic interface.
The problem is that, now, at each time I try to instance a class from "mydll.dll" in debbuger mode in C#, I have the following "InvalidCastException"
Unable to cast COM object of type mydll.ClassFrommydll to interface type mydll._ClassFrommydll'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{384FB79F-B636-4655-9441-8222692AB8AE}' failed due to the following error: No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE)).
I tried to re-reference the dll in question ... but that does not change anything.
Any idea on what it could come from ?
Many many thanks to all of yopu who can help. Have been stuck with this problem for days now. Start to feel the pressure ...
回答1:
mark the main class [STAThread] and your problem will be solved
回答2:
I ran into this exact problem using the IBM Dll's.
[STAThread]
static void Main(string[] args)
{
}
Fixed the issue for me with all COM interfaces being usable and the exception cleared
回答3:
Remove all GUIDs and "ComVisible" attributes from the class, then switch the [assembly: ComVisible(true)] attribute in the AssemblyInfo-File to 'true'.
来源：https://stackoverflow.com/questions/9788135/exception-from-hresult-0x80004002-e-nointerface