如何在SetCompatibleTextRenderingDefault抛出InvalidOperationException时找出IWin32Window已创建的内容？

Question

After major refactoring, I run my WinForms application and it immediately crashes on Application.SetCompatibleTextRenderingDefault(false) . In general, I understand what causes this: an IWin32Window has already been created.

My problem is that for the life of me I can't figure out what such an object (or objects?) have been instantiated. "Where" it was instantiated comes as a hopefully easier later question :) The line that throws is literally the second line of my code: if I step into my application (launching with F10 rather than F5, to be clear), it goes through the usual Application.EnableVisualStyles() without trouble, then it stops on the second line.

Is there a way to "inspect" created windows? I'm looking for any solution, lines of code, debugger features, external programs, anything. Thank you.

PLEASE NOTE that it's evident to me that I must have messed something up during my refactoring. I couldn't compile for three days, so it's most likely that I created the bug myself. I'm asking whether there's a way to confidently find the offending IWin32Window object.

UPDATE

I've added the following code at the very beginning of Program.Main() :

        var thisProcess = System.Diagnostics.Process.GetCurrentProcess();
        if (thisProcess != null)
        {
            var mainWindow = thisProcess.MainWindowHandle;
        }

Well, mainWindow is (a pointer to) zero.

Answer 1

You have to look for code that runs before your Main() method runs. Not a lot of candidates for such code, only the static constructor (aka type initializer) for the Program class qualifies. You'd know if you had written one, and could set a breakpoint on it, the less obvious case is a static variable in the Program class with a field initializer. Not actually supported by the CLR, the C# compiler works around it by creating that static constructor itself and moving the code of the field initializer.

If knowing that it is caused by a field initializer doesn't help then you can consider setting a breakpoint on the relevant framework method. That does require some insight in how it works internally and there is no simple shortcut for that. Well, other than asking at SO :)

First use Tools > Options > Debugging > General and untick "Just My Code". This isn't your code. Next use Debug > New Breakpoint > Function Breakpoint > type "System.Windows.Forms.NativeWindow.AddWindowToTable". That is the internal method that stores a reference to any created window, ensuring that the .NET class wrapper object does not get garbage collected too early.

Press F5, the Call Stack window points at the evil-doer.