How do I find the position / location of a window given a hWnd without NativeMethods?

Question

I'm currently working with WatiN, and finding it to be a great web browsing automation tool. However, as of the last release, it's screen capturing functionality seems to be lacking. I've come up with a workable solution for capturing screenshots from the screen (independently generating code similar to this StackOverflow question) in addition to some code by Charles Petzold. Unfortunately, there is a missing component: Where is the actual window?

WatiN conveniently provides the browser's hWnd to you, so we can (with this simplified example) get set to copy an image from the screen, like so:

// browser is either an WatiN.Core.IE or a WatiN.Core.FireFox...
IntPtr hWnd = browser.hWnd;
string filename = "my_file.bmp";
using (Graphics browser = Graphics.FromHwnd(browser.hWnd) )
using (Bitmap screenshot = new Bitmap((int)browser.VisibleClipBounds.Width,
                                      (int)browser.VisibleClipBounds.Height,
                                      browser))
using (Graphics screenGraphics = Graphics.FromImage(screenshot))
{
    int hWndX = 0; // Upper left of graphics?  Nope, 
    int hWndY = 0; // this is upper left of the entire desktop!

    screenGraphics.CopyFromScreen(hWndX, hWndY, 0, 0, 
                          new Size((int)browser.VisibileClipBounds.Width,
                                   (int)browser.VisibileClipBounds.Height));
    screenshot.Save(filename, ImageFormat.Bmp);
}

Success! We get screenshots, but there's that problem: hWndX and hWndY always point to the upper left most corner of the screen, not the location of the window we want to copy from.

I then looked into Control.FromHandle, however this seems to only work with forms you created; this method returns a null pointer if you pass the hWnd into it.

Then, further reading lead me to switch my search criteria...I had been searching for 'location of window' when most people really want the 'position' of the window. This lead to another SO question that talked about this, but their answer was to use native methods.

So, Is there a native C# way of finding the position of a window, only given the hWnd (preferably with only .NET 2.0 era libraries)?

Answer 1

I just went through this on a project and was unable to find any managed C# way.

To add to Reed's answer the P/Invoke code is:

 [DllImport("user32.dll", SetLastError = true)]
 [return: MarshalAs(UnmanagedType.Bool)]
 static extern bool GetWindowRect(IntPtr hWnd, ref RECT lpRect);
 [StructLayout(LayoutKind.Sequential)]
 private struct RECT
 {
     public int Left;
     public int Top;
     public int Right;
     public int Bottom;
  }

Call it as:

  RECT rct = new RECT();
  GetWindowRect(hWnd, ref rct);

Answer 2

No - if you didn't create the form, you have to P/Invoke GetWindowRect. I don't believe there is a managed equivalent.