C# Windows程序窗口置前台的几种方法

这个是从别的地方看来的，放我这里

第一种：SetForegroundWindow，这个方法时灵时不灵。有人说，在自己的程序里把自己的窗口之前一般就不灵，而置前其它程序的窗口就灵。我觉得这是有原因的：当一个程序运行这个函数的时候，我们可以想象，如果是用鼠标操作，那么当前窗口实际上正在操作，很可能在瞬间离开后，焦点又回来了，那么看上去更就没有吧其它窗口置前的效果，所以这个函数内部可能做了延迟，略等一下，在这个时间内，当前窗口不会被置前。就是这个时间，函数已经调用完成，所以看上去，自己的窗口并没有置前。

第二种：SwitchToThisWindow，这个方法很好使，还会把最小化的窗口复原。但是Windows说，这个函数以后可能不支持。但是我觉得可以放心使用，Windows当前一般就那几个版本，程序不会计划运行100年不升级吧。这个函数可以直接链接，但是XP以前的版本可能不行，所以，使用动态加载可能保险点。动态加载代码：

1. typedef void (WINAPI*PROCSWITCHTOTHISWINDOW)(HWND,BOOL);
2. PROCSWITCHTOTHISWINDOW SwitchToThisWindow;
3. HMODULE hUser32 = GetModuleHandle(L"user32");
4. SwitchToThisWindow = (PROCSWITCHTOTHISWINDOW)GetProcAddress(hUser32,"SwitchToThisWindow");
5. SwitchToThisWindow(frame,1);

第三种方法：BringWindowToTop，这个函数比上一个功能少点，实质是调用SetWindowPos函数。

我的具体用法是这样子

//[DllImport("user32.dll")]
//public static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
[DllImport("user32.dll ", SetLastError = true)]
static extern void SwitchToThisWindow(IntPtr hWnd, bool fAltTab);

//[DllImport("user32.dll", EntryPoint = "ShowWindow", CharSet = CharSet.Auto)]
//public static extern int ShowWindow(IntPtr hwnd, int nCmdShow);
public const int SW_RESTORE = 9;
public static IntPtr formhwnd;

Process[] MyProcesses = Process.GetProcesses();
ProcessStartInfo startInfo = new ProcessStartInfo();
startInfo.WorkingDirectory = @"D:\开发区工作\钢筋软件\开发资料\2017\源代码\MTC部分\廊坊凯博\KBMES\";
startInfo.FileName = "Client.exe";
bool temp = false;
foreach (Process MyProcess in MyProcesses)
{
if (MyProcess.ProcessName == "Client")
{
//IntPtr handle = MyProcess.MainWindowHandle;
//ShowWindow(handle,1);
temp = true;
SwitchToThisWindow(MyProcess.MainWindowHandle,true);
break;
}
}
if (temp == false)
Process.Start(startInfo);

后面还看到

SwitchToThisWindow这个是遗留函数，也就是微软为了和以前版本windows兼容而留下来的，以后的版本可能会被移除。
SetForegroundWindow就是推荐的函数。
SetActiveWindow这三者有什么区别和联系 SetActiveWindow不能激活后台程序，也就是窗口被隐藏了，不能用它激活。

ShowWindow的API函数是显示窗口，

它的第二个参数是决定窗体的状态的。

Value	Meaning
SW_FORCEMINIMIZE 11	Minimizes a window, even if the thread that owns the window is not responding. This flag should only be used when minimizing windows from a different thread.
SW_HIDE 0	Hides the window and activates another window.
SW_MAXIMIZE 3	Maximizes the specified window.
SW_MINIMIZE 6	Minimizes the specified window and activates the next top-level window in the Z order.
SW_RESTORE 9	Activates and displays the window. If the window is minimized or maximized, the system restores it to its original size and position. An application should specify this flag when restoring a minimized window.
SW_SHOW 5	Activates the window and displays it in its current size and position.
SW_SHOWDEFAULT 10	Sets the show state based on the SW_ value specified in the STARTUPINFO structure passed to the CreateProcess function by the program that started the application.
SW_SHOWMAXIMIZED 3	Activates the window and displays it as a maximized window.
SW_SHOWMINIMIZED 2	Activates the window and displays it as a minimized window.
SW_SHOWMINNOACTIVE 7	Displays the window as a minimized window. This value is similar to SW_SHOWMINIMIZED, except the window is not activated.
SW_SHOWNA 8	Displays the window in its current size and position. This value is similar to SW_SHOW, except that the window is not activated.
SW_SHOWNOACTIVATE 4	Displays a window in its most recent size and position. This value is similar to SW_SHOWNORMAL, except that the window is not activated.
SW_SHOWNORMAL 1	Activates and displays a window. If the window is minimized or maximized, the system restores it to its original size and position. An application should specify this flag when displaying the window for the first time.

好吧，这些都在C#用到了非托管类的API了，不知道VS里面的类有没有这样的功能。