c# winform窗口一直置顶显示在桌面最上方或最底层的方法

一、

在最前面：
using System.Runtime.InteropServices;
在定义部分引入下面两个函数：
[DllImport( "user32 ")]
private static extern IntPtr FindWindow(string lpClassName,string lpWindowName);
[DllImport( "user32 ")]
private static extern IntPtr SetParent(IntPtr hWndChild, IntPtr hWndNewParent);
在窗体On_Load事件中添加（Santos的代码）：
IntPtr hDeskTop=FindWindow( "Progman ", "Program Manager ");
SetParent(this.Handle,hDeskTop);
另一个方法可以修改桌面壁纸实现
经测试，win2000--win2003 、xp下嵌入桌面，不支持vista和win7以上系统

二、

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;
namespace ShowInDesk
{
publicpartialclass Form1 : Form
{
IntPtr hDesktop;
publicconstint GW_CHILD =5;
public Form1()
{
InitializeComponent();
this.hDesktop = GetDesktopHandle(DesktopLayer.Progman);
EmbedDesktop(this, this.Handle, this.hDesktop);
isMouseDown =false;
}
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;
}
publicvoid EmbedDesktop(Object embeddedWindow, IntPtr childWindow, IntPtr parentWindow)
{
Form window = (Form)embeddedWindow;
HandleRef HWND_BOTTOM =new HandleRef(embeddedWindow, new IntPtr(1));
constint 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);
}
}
}

2、

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
namespace ShowInDesk
{
class Win32Support
{
[DllImport("user32.dll", CharSet = CharSet.Auto)]
publicstaticextern IntPtr FindWindow(string className, string windowName);
[DllImport("user32.dll", CharSet = CharSet.Auto, ExactSpelling =true)]
publicstaticextern IntPtr GetWindow(HandleRef hWnd, int nCmd);
[DllImport("user32.dll")]
publicstaticextern IntPtr SetParent(IntPtr child, IntPtr parent);
[DllImport("user32.dll", EntryPoint ="GetDCEx", CharSet = CharSet.Auto, ExactSpelling =true)]
publicstaticextern IntPtr GetDCEx(IntPtr hWnd, IntPtr hrgnClip, int flags);
[DllImport("user32.dll", CharSet = CharSet.Auto, ExactSpelling =true)]
publicstaticexternbool SetWindowPos(HandleRef hWnd, HandleRef hWndInsertAfter, int x, int y, int cx, int cy, int flags);
[DllImport("user32.dll")]
publicstaticexternint ReleaseDC(IntPtr window, IntPtr handle);
}
}

3、

namespace ShowInDesk
{
publicenum DesktopLayer
{
Progman =0,
SHELLDLL =1,
FolderView =2
}
}

三、
入桌面窗口最底层，并提供详细的实现代码供参考。
此类将窗体永远置于窗口最底层。
首先, 调用一些User32.dll的WinAPI函数。

internal class User32
{
public const int SE_SHUTDOWN_PRIVILEGE =0x13;
[DllImport("user32.dll")]
public static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
[DllImport("user32.dll")]
public static extern IntPtr SetParent(IntPtr hWndChild, IntPtr hWndNewParent);
[DllImport("user32.dll")]
public static externbool SetWindowPos(IntPtr hWnd, int hWndInsertAfter, int X, int Y, int cx,
int cy, uint uFlags);
}

然后, 在WinForm里面：

public MainForm()
{
InitializeComponent();
try
{
if (Environment.OSVersion.Version.Major <6)
{
base.SendToBack();
IntPtr hWndNewParent = User32.FindWindow("Progman", null);
User32.SetParent(base.Handle, hWndNewParent);
}
else
{
User32.SetWindowPos(base.Handle, 1, 0, 0, 0, 0, User32.SE_SHUTDOWN_PRIVILEGE);
}
}
catch (ApplicationException exx)
{
MessageBox.Show(this, exx.Message, "Pin to Desktop");
}
}
private void MainForm_Activated(object sender, EventArgs e)
{
if (Environment.OSVersion.Version.Major >=6)
{
User32.SetWindowPos(base.Handle, 1, 0, 0, 0, 0, User32.SE_SHUTDOWN_PRIVILEGE);
}
}
private void MainForm_Paint(object sender, PaintEventArgs e)
{
if (Environment.OSVersion.Version.Major >=6)
{
User32.SetWindowPos(base.Handle, 1, 0, 0, 0, 0, User32.SE_SHUTDOWN_PRIVILEGE);
}
}

以上介绍的就是C#如何让WinForm嵌入桌面窗口最底层，希望对你有所帮助。