C#中使用FindWindow函数详解 从标题获取句柄

FindWindow 用来根据类名和窗口名来得到窗口句柄的。但是这个函数不能查找子窗口，也不区分大小写。

如果要从一个窗口的子窗口中查找需要使用FindWindowEX。

1.在C#中使用方法如下：

[DllImport("User32.dll", EntryPoint = "FindWindow")]   
        private static extern IntPtr FindWindow(string lpClassName,string lpWindowName);   
[DllImport("User32.dll", EntryPoint = "FindWindowEx")]   
        private static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpClassName, string lpWindowName); 
[DllImport("User32.dll", EntryPoint = "FindWindow")]
        private static extern IntPtr FindWindow(string lpClassName,string lpWindowName);
[DllImport("User32.dll", EntryPoint = "FindWindowEx")]
        private static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpClassName, string lpWindowName);

2. 实例参考：

IntPtr hWnd = FindWindow(null, "test Demo");

这样会查找所有title是"test Demo"的窗口。

参考下面的资料解释

3. FindWindow参数详解：

Parameters

lpClassName
[in] Pointer to a null-terminated string that specifies the class name or a class atom created by a previous call to the RegisterClass or RegisterClassEx function. The atom must be in the low-order word of lpClassName; the high-order word must be zero. 
If lpClassName points to a string, it specifies the window class name. The class name can be any name registered with RegisterClass or RegisterClassEx, or any of the predefined control-class names.

If lpClassName is NULL, it finds any window whose title matches the lpWindowName parameter.

lpWindowName
[in] Pointer to a null-terminated string that specifies the window name (the window's title). If this parameter is NULL, all window names match. 
Return Value

If the function succeeds, the return value is a handle to the window that has the specified class name and window name.

If the function fails, the return value is NULL. To get extended error information, call GetLastError.

Remarks

If the lpWindowName parameter is not NULL, FindWindow calls the GetWindowText function to retrieve the window name for comparison. For a description of a potential problem that can arise, see the Remarks for GetWindowText.

To check if the Microsoft IntelliType version 1.x software is running, call FindWindow as follows:

Copy Code
FindWindow("MSITPro::EventQueue",NULL);   To check if the IntelliType version 2.0 software is running, call FindWindow as follows:

Copy Code
FindWindow("Type32_Main_Window", NULL);   If the IntelliType software is running, it sends WM_APPCOMMAND messages to the application. Otherwise the application must install a hook to receive WM_APPCOMMAND messages.

Microsoft Windows 95 or later: FindWindowW is supported by the Microsoft Layer for Unicode (MSLU). To use this, you must add certain files to your application, as outlined in Microsoft Layer for Unicode on Windows 95/98/Me Systems.

Example

For an example, see Retrieving the Number of Mouse Wheel Scroll Lines.

Function Information

Minimum DLL Version user32.dll 
Header Declared in Winuser.h, include Windows.h 
Import library User32.lib 
Minimum operating systems Windows 95, Windows NT 3.1 
Unicode Implemented as ANSI and Unicode versions. 
本文来自：http://blog.csdn.net/soief/archive/2009/04/20/4094476.aspx