#region 设置桌面为父窗口
IntPtr hDesktop;
public const int GW_CHILD = 5;

public IntPtr GetDesktopHandle(DesktopLayer layer)
{
//hWnd = new HandleRef();
HandleRef hWnd;
IntPtr hDesktop = new IntPtr();
switch (layer)
{
case DesktopLayer.Progman:
hDesktop = Win32Support.FindWindow("Progman", null);//第一层桌面
break;
case DesktopLayer.SHELLDLL:
hDesktop = Win32Support.FindWindow("Progman", null);//第一层桌面
hWnd = new HandleRef(this, hDesktop);
hDesktop = Win32Support.GetWindow(hWnd, GW_CHILD);//第2层桌面
break;
case DesktopLayer.FolderView:
hDesktop = Win32Support.FindWindow("Progman", null);//第一层桌面
hWnd = new HandleRef(this, hDesktop);
hDesktop = Win32Support.GetWindow(hWnd, GW_CHILD);//第2层桌面
hWnd = new HandleRef(this, hDesktop);
hDesktop = Win32Support.GetWindow(hWnd, GW_CHILD);//第3层桌面
break;
}
return hDesktop;
}

public void EmbedDesktop(Object embeddedWindow, IntPtr childWindow, IntPtr parentWindow)
{
Form window = (Form)embeddedWindow;
HandleRef HWND_BOTTOM = new HandleRef(embeddedWindow, new IntPtr(1));
const int SWP_FRAMECHANGED = 0x0020;//发送窗口大小改变消息
Win32Support.SetParent(childWindow, parentWindow);
Win32Support.SetWindowPos(new HandleRef(window, childWindow), HWND_BOTTOM, 300, 300, window.Width, window.Height, SWP_FRAMECHANGED);
}

private void button1_Click(object sender, EventArgs e)
{

}

class Win32Support
{

[DllImport("user32.dll", CharSet = CharSet.Auto)]
public static extern IntPtr FindWindow(string className, string windowName);
[DllImport("user32.dll", CharSet = CharSet.Auto, ExactSpelling = true)]
public static extern IntPtr GetWindow(HandleRef hWnd, int nCmd);
[DllImport("user32.dll")]
public static extern IntPtr SetParent(IntPtr child, IntPtr parent);
[DllImport("user32.dll", EntryPoint = "GetDCEx", CharSet = CharSet.Auto, ExactSpelling = true)]
public static extern IntPtr GetDCEx(IntPtr hWnd, IntPtr hrgnClip, int flags);
[DllImport("user32.dll", CharSet = CharSet.Auto, ExactSpelling = true)]
public static extern bool SetWindowPos(HandleRef hWnd, HandleRef hWndInsertAfter, int x, int y, int cx, int cy, int flags);
[DllImport("user32.dll")]
public static extern int ReleaseDC(IntPtr window, IntPtr handle);
}

public enum DesktopLayer
{
Progman = 0,
SHELLDLL = 1,
FolderView = 2
}
#endregion

public Form1()
{
InitializeComponent();
this.hDesktop = GetDesktopHandle(DesktopLayer.Progman);
EmbedDesktop(this, this.Handle, this.hDesktop);
}