using System;
using System.Diagnostics;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;
 
namespace WinTest
{
    public partial class Form1 : Form
    {
        [DllImport("user32")]
        public static extern int SetWindowLong(IntPtr hWnd, int nIndex, int newValue);
 
        [DllImport("user32.dll")]
        public static extern bool GetClientRect(IntPtr hWnd, out RECT lpRect);
 
        [DllImport("user32.dll", SetLastError = true)]
        public static extern IntPtr SetParent(IntPtr child, IntPtr newParent);
 
        [DllImport("user32.dll")]
        public static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndAfter, Int32 X, Int32 Y, Int32 cx, Int32 cy, Int32 uFlags);
 
        [DllImport("user32.dll", SetLastError = true)]
        public static extern int GetWindowLong(IntPtr hWnd, int nIndex);
 
        public const int GWL_STYLE = (-16);
 
        IntPtr _childHWnd;
        IntPtr _parentHWnd;
 
        public Form1()
        {
            InitializeComponent();
            Process p = new Process();
            p.StartInfo = new ProcessStartInfo("notepad");
            p.Start();
            p.WaitForInputIdle();
            _parentHWnd = this.Handle;
            _childHWnd = p.MainWindowHandle;
        }
 
        private void Form1_Shown(object sender, EventArgs e)
        {
            int style = GetWindowLong(_childHWnd, GWL_STYLE);
            int newStyle = style;
            newStyle |= (int)WindowStyles.WS_CHILD;
 
            RECT rect = new RECT();
            GetClientRect(_parentHWnd, out rect);
            SetParent(_childHWnd, _parentHWnd);
            SetWindowPos(_childHWnd, IntPtr.Zero, 0, 0, rect.Width, rect.Height, 0);
            SetWindowLong(_childHWnd, GWL_STYLE, newStyle);
        }
    }
 
    [Flags]
    enum WindowStyles
    {
        WS_BORDER = 0x00800000,
        WS_CAPTION = 0x00C00000,
        WS_CHILD = 0x40000000,
        WS_CHILDWINDOW = 0x40000000,
        WS_CLIPCHILDREN = 0x02000000,
        WS_CLIPSIBLINGS = 0x04000000,
        WS_DISABLED = 0x08000000,
        WS_DLGFRAME = 0x00400000,
        WS_GROUP = 0x00020000,
        WS_HSCROLL = 0x00100000,
        WS_ICONIC = 0x20000000,
        WS_MAXIMIZE = 0x01000000,
        WS_MAXIMIZEBOX = 0x00010000,
        WS_MINIMIZE = 0x20000000,
        WS_MINIMIZEBOX = 0x00020000,
        WS_OVERLAPPED = 0x00000000,
        WS_OVERLAPPEDWINDOW = (int)WS_OVERLAPPED | (int)WS_CAPTION | (int)WS_SYSMENU | (int)WS_THICKFRAME | (int)WS_MINIMIZEBOX | (int)WS_MAXIMIZEBOX,
        WS_POPUP = unchecked((int)0x80000000),
        WS_POPUPWINDOW = (int)WS_POPUP | (int)WS_BORDER | (int)WS_SYSMENU,
        WS_SIZEBOX = 0x00040000,
        WS_SYSMENU = 0x00080000,
        WS_TABSTOP = 0x00010000,
        WS_THICKFRAME = 0x00040000,
        WS_TILED = 0x00000000,
        WS_TILEDWINDOW = (int)WS_OVERLAPPED | (int)WS_CAPTION | (int)WS_SYSMENU | (int)WS_THICKFRAME | (int)WS_MINIMIZEBOX | (int)WS_MAXIMIZEBOX,
        WS_VISIBLE = 0x10000000,
        WS_VSCROLL = 0x00200000
    }
 
    [StructLayout(LayoutKind.Sequential)]
    public struct RECT
    {
        int _Left;
        int _Top;
        int _Right;
        int _Bottom;
 
        public RECT(RECT Rectangle)
            : this(Rectangle.Left, Rectangle.Top, Rectangle.Right, Rectangle.Bottom)
        {
        }
        public RECT(int Left, int Top, int Right, int Bottom)
        {
            _Left = Left;
            _Top = Top;
            _Right = Right;
            _Bottom = Bottom;
        }
 
        public int X
        {
            get
            {
                return _Left;
            }
            set
            {
                _Right -= (_Left - value);
                _Left = value;
            }
        }
        public int Y
        {
            get
            {
                return _Top;
            }
            set
            {
                _Bottom -= (_Top - value);
                _Top = value;
            }
        }
        public int Left
        {
            get
            {
                return _Left;
            }
            set
            {
                _Left = value;
            }
        }
        public int Top
        {
            get
            {
                return _Top;
            }
            set
            {
                _Top = value;
            }
        }
        public int Right
        {
            get
            {
                return _Right;
            }
            set
            {
                _Right = value;
            }
        }
        public int Bottom
        {
            get
            {
                return _Bottom;
            }
            set
            {
                _Bottom = value;
            }
        }
        public int Height
        {
            get
            {
                return _Bottom - _Top;
            }
            set
            {
                _Bottom = value + _Top;
            }
        }
        public int Width
        {
            get
            {
                return _Right - _Left;
            }
            set
            {
                _Right = value + _Left;
            }
        }
        public Point Location
        {
            get
            {
                return new Point(Left, Top);
            }
            set
            {
                _Right -= (_Left - value.X);
                _Bottom -= (_Top - value.Y);
                _Left = value.X;
                _Top = value.Y;
            }
        }
        public Size Size
        {
            get
            {
                return new Size(Width, Height);
            }
            set
            {
                _Right = value.Width + _Left;
                _Bottom = value.Height + _Top;
            }
        }
 
        public static implicit operator Rectangle(RECT Rectangle)
        {
            return new Rectangle(Rectangle.Left, Rectangle.Top, Rectangle.Width, Rectangle.Height);
        }
        public static implicit operator RECT(Rectangle Rectangle)
        {
            return new RECT(Rectangle.Left, Rectangle.Top, Rectangle.Right, Rectangle.Bottom);
        }
        public static bool operator ==(RECT Rectangle1, RECT Rectangle2)
        {
            return Rectangle1.Equals(Rectangle2);
        }
        public static bool operator !=(RECT Rectangle1, RECT Rectangle2)
        {
            return !Rectangle1.Equals(Rectangle2);
        }
 
        public override string ToString()
        {
            return "{Left: " + _Left + "; " + "Top: " + _Top + "; Right: " + _Right + "; Bottom: " + _Bottom + "}";
        }
 
        public override int GetHashCode()
        {
            return ToString().GetHashCode();
        }
 
        public bool Equals(RECT Rectangle)
        {
            return Rectangle.Left == _Left && Rectangle.Top == _Top && Rectangle.Right == _Right && Rectangle.Bottom == _Bottom;
        }
 
        public override bool Equals(object Object)
        {
            if (Object is RECT)
            {
                return Equals((RECT)Object);
            }
            else if (Object is Rectangle)
            {
                return Equals(new RECT((Rectangle)Object));
            }
            return false;
        }
    }
}