Move a window on keypress + mouse (like linux ALT + mouse down)

Question

Simple, i want to move a windows pressing ALT+MOUSE, like linux os (ALT+drag).

It\'s possible to pass a win32 api (move api) to the windows interested clicking on it?

Answer 1

I worked this out my self, came up with something interesting of my own calculations, worked perfectly for me, for any window (any active foreground window). Kinda long, but really easy to understand if you follow along the comments, hope it helps :) The way it works, is that you press a certain registered key-combo, like Ctrl+Alt+M and the mouse will stick in the center of an active window, you move the mouse, the windows follows it, press the SAME combo again, to release, no need for mouse clicks or anything.

public void MoveWindow_AfterMouse()
    {
      // 1- get a handle to the foreground window (or any window that you want to move).
      // 2- set the mouse pos to the window's center.
      // 3- let the window move with the mouse in a loop, such that:
      //    win(x) = mouse(x) - win(width)/2   
      //    win(y) = mouse(y) - win(height)/2
      // This is because the origin (point of rendering) of the window, is at its top-left corner and NOT its center!

      // 1- 
      IntPtr hWnd = WinAPIs.GetForegroundWindow();

      // 2- Then:
      // first we need to get the x, y to the center of the window.
      // to do this, we have to know the width/height of the window.
      // to do this, we could use GetWindowRect which will give us the coords of the bottom right and upper left corners of the window,
      // with some math, we could deduce the width/height of the window.
      // after we do that, we simply set the x, y coords of the mouse to that center.
      RECT wndRect = new RECT();
      WinAPIs.GetWindowRect(hWnd, out wndRect);
      int wndWidth = wndRect.right - wndRect.left;
      int wndHeight = wndRect.bottom - wndRect.top; // cuz the more you go down, the more y value increases.
      Point wndCenter = new Point(wndWidth / 2, wndHeight / 2); // this is the center of the window relative to itself.
      WinAPIs.ClientToScreen(hWnd, out wndCenter); // this will make its center relative to the screen coords.
      WinAPIs.SetCursorPos(wndCenter.X, wndCenter.Y);

      // 3- Moving :)))
      while (true)
      {
        Point cursorPos = new Point();
        WinAPIs.GetCursorPos(out cursorPos);
        int xOffset = cursorPos.X - wndWidth / 2;
        int yOffset = cursorPos.Y - wndHeight / 2;
        WinAPIs.MoveWindow(hWnd, xOffset, yOffset, wndWidth, wndHeight, true);
        Thread.Sleep(25);
      }
    }

And now:

int moveCommandToggle = 0;
protected override void WndProc(ref Message m)
{
   if (m.Msg == 0x0312)
   {
     int keyID = m.WParam.ToInt32();
     if(keyID == some_key_combo_you_registered_for_the_moving)
     {
         if (moveCommandToggle++ % 2 == 0)
         {
            mover = new Thread(() => MoveWindow_AfterMouse());
            mover.Start();
         }
         else mover.Abort();
      }
    }
 }

If you're wondering about RECT:

  public struct RECT
  {
    public int left;    // xCoor of upper left corner.
    public int top;     // yCoor of upper left corner.
    public int right;   // xCoor of lower right corner.
    public int bottom;  // yCoor of lower right corner.
  };

WinAPIs was just a static class that I did my DllImports in.