CODEWITHSUNDEEP
c#.net
Jim Bucciferro
Jim Bucciferro

Reputation: 1

C# - Windows Forms - Windows 7 - Overlay another application's window

I have an application that needs to overlay another application's window. As the overlayed moves I need my application to move along with it.

I am using the following code to get the window and position my window over it.

public static void DockToWindow(IntPtr hwnd, IntPtr hwndParent)
    {
        RECT rectParent = new RECT();
        GetWindowRect(hwndParent, ref rectParent);

        RECT clientRect = new RECT();
        GetWindowRect(hwnd, ref clientRect);
        SetWindowPos(hwnd, hwndParent, rectParent.Left, 
                                     (rectParent.Bottom - (clientRect.Bottom - 
                                      clientRect.Top)),  // Left position
                                     (rectParent.Right - rectParent.Left),
                                     (clientRect.Bottom - clientRect.Top),
                                     SetWindowPosFlags.SWP_NOZORDER);

     }

I also set the form.TopMost to true. The problem I am having is that the overlay takes focus away from the overlayed window. I just want my overlay to sit on top of this window but not steal focus. If the user clicks on the overlayed window I want it to work as it did before I placed the overlay. However, if the user clicks on the overlay I need to capture the mouse on the overlay.

Any ideas? Thanks

Upvotes: 0

Views: 1461

Answers (3)

Jim Bucciferro
Jim Bucciferro

Reputation: 1

I was able to find a solution to this issue by updating the SetWindowPos code to use the overlay form's Left,Top,Right, and Bottom properties instead of using GetWindowRect.

 RECT rect = new RECT();
 GetWindowRect(hostWindow, ref rect);
 SetWindowPos(this.Handle, NativeWindows.HWND_TOPMOST,
                                         rect.Left+10,
                                         rect.Bottom - (Bottom - Top),
                                        (rect.Right - rect.Left),
                                         Bottom - Top,
                                         0);

This code aligns the overlay window along the bottom edge of the host window. The problem I have now is that my overlay is on top of all windows, not just the window I want to overlay. I've tried HWND_TOP which does the same thing, and the overlayed window handle, which places my overlay beneath the window.

Any ideas - do I need to use SetParent() ?

Upvotes: 0

LarsTech
LarsTech

Reputation: 81610

From Floating Controls, Tooltip-style, try this on your overlay form:

private const int WM_NCHITTEST             = 0x0084;
private const int HTTRANSPARENT            = (-1);

/// <summary>
/// Overrides the standard Window Procedure to ensure the
/// window is transparent to all mouse events.
/// </summary>
/// <param name="m">Windows message to process.</param>
protected override void WndProc(ref Message m)
{
  if (m.Msg == WM_NCHITTEST)
  {
    m.Result = (IntPtr) HTTRANSPARENT;
  }
  else
  {
    base.WndProc(ref m);
  }
}

Upvotes: 0

krembanan
krembanan

Reputation: 1428

In winforms, you can avoid focus-setting by overriding ShowWithoutActivation

protected override bool ShowWithoutActivation
{
  get { return true; }
}

http://msdn.microsoft.com/en-us/library/system.windows.forms.form.showwithoutactivation.aspx

Upvotes: 1

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