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。