Find if process is responding without using System.Diagnostics.Process.Responding

Question

Good day everyone.

This problem was part of another one which it as been solved, i realized that what i thought it was the problem after all, it was

Answer 1

IE is special because each tab has its own process plus there is an additional parent IE process. In fact, only the parent process will have a valid MainWindowHandle.

Did you check whether MainWindowHandle is null for all these processes? If it isn't I think your code should work as expected on XP as well.

Update

Since checking all IE instances didn't help, the next thing I would try is to modify the timeout that is used by Process.Responding. The property internally calls the SendMessageTimeout api function and then checks the return value whether a timeout occurred. If so, the process is assumed to be hanging. The timeout is a hard-coded value of 5 seconds.

You can call SendMessageTimeout yourself using P/Invoke and vary the timeout. Possibly a shorter value would give better results on Windows XP:

[DllImport("user32.dll", CharSet=CharSet.Auto)]
static extern IntPtr SendMessageTimeout(
    HandleRef hWnd, 
    int msg, 
    IntPtr wParam, 
    IntPtr lParam, 
    int flags, 
    int timeout, 
    out IntPtr pdwResult);

const int SMTO_ABORTIFHUNG = 2;

bool IsResponding(Process process)
{
    HandeRef handleRef = new HandleRef(process, process.MainWindowHandle);

    int timeout = 2000;
    IntPtr lpdwResult;

    IntPtr lResult = SendMessageTimeout(
        handleRef, 
        0, 
        IntPtr.Zero, 
        IntPtr.Zero, 
        SMTO_ABORTIFHUNG, 
        timeout, 
        out lpdwResult);

    return lResult != IntPtr.Zero;
}