How to set the height of a window using c#?

Question

Is it possible to set the height of a window using the window handle or process handle?

I have the following so far, assume the application in question is notepad.

Answer 1

You should be able to use the Win32 SetWindowPos function (use for both position and size). Here's a link for how to do it in C#.

Here's a quick sample. This will move notepad to (10,10) on the screen, and resize it to (450,450):

class Program
{
    [DllImport("user32.dll")]
    [return: MarshalAs(UnmanagedType.Bool)]
    static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int X, int Y, int cx, int cy, SetWindowPosFlags uFlags);

    static void Main(string[] args)
    {
        Console.WriteLine("Start notepad and hit any key...");
        Console.ReadKey(true);
        Process[] processes = Process.GetProcessesByName("notepad");

        foreach (Process p in processes)
        {
            var handle = p.MainWindowHandle;

            SetWindowPos(handle, new IntPtr(SpecialWindowHandles.HWND_TOP), 10,10,450,450,SetWindowPosFlags.SWP_SHOWWINDOW);

            break;

        }

    }
}

public enum SpecialWindowHandles
{
    HWND_TOP = 0,
    HWND_BOTTOM = 1,
    HWND_TOPMOST = -1,
    HWND_NOTOPMOST = -2
}

[Flags]
public enum SetWindowPosFlags : uint
{
    SWP_ASYNCWINDOWPOS = 0x4000,

    SWP_DEFERERASE = 0x2000,

    SWP_DRAWFRAME = 0x0020,

    SWP_FRAMECHANGED = 0x0020,

    SWP_HIDEWINDOW = 0x0080,

    SWP_NOACTIVATE = 0x0010,

    SWP_NOCOPYBITS = 0x0100,

    SWP_NOMOVE = 0x0002,

    SWP_NOOWNERZORDER = 0x0200,

    SWP_NOREDRAW = 0x0008,

    SWP_NOREPOSITION = 0x0200,

    SWP_NOSENDCHANGING = 0x0400,

    SWP_NOSIZE = 0x0001,

    SWP_NOZORDER = 0x0004,

    SWP_SHOWWINDOW = 0x0040,
}

Answer 2

This is how I would do it:

using System;
using System.Diagnostics;
using System.Runtime.InteropServices;

namespace ConsoleApplication1
{
    class Program
    {
        [StructLayout(LayoutKind.Sequential)]
        public struct RECT
        {
            public int left;
            public int top;
            public int right;
            public int bottom;
        }

        [DllImport("user32.dll", SetLastError = true)]
        static extern bool GetWindowRect(IntPtr hWnd, ref RECT Rect);

        [DllImport("user32.dll", SetLastError = true)]
        static extern bool MoveWindow(IntPtr hWnd, int X, int Y, int Width, int Height, bool Repaint);

        static void Main(string[] args)
        {
            Process[] processes = Process.GetProcessesByName("notepad");
            foreach (Process p in processes)
            {
                IntPtr handle = p.MainWindowHandle;
                RECT Rect = new RECT();
                if (GetWindowRect(handle, ref Rect))
                    MoveWindow(handle, Rect.left, Rect.right, Rect.right-Rect.left, Rect.bottom-Rect.top + 50, true);
            }
        }
    }
}

While you can do it with SetWindowPos, and SetWindowPos is the newer and more capable API, MoveWindow is just easier to call.