user32的使用

通过代码查询特定的窗口，并在文本框中输入文字然后单击"OK"按钮
需要查找的Dialog
使用Spy++查看窗口信息
通过代码实现功能
 1     class Program
 2     {
 3         //define method
 4 
 5         /// <summary>
 6         /// 查找顶级窗口,如果有指定的类名和窗口的名字则表示成功返回一个窗口的句柄。否则返回零。
 7         /// </summary>
 8         /// <param name="lpClassName">lpClassName参数指向类名</param>
 9         /// <param name="lpWindowName">lpWindowName指向窗口名</param>
10         /// <returns></returns>
11         [DllImport("User32.dll", EntryPoint = "FindWindow")]
12         private static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
13 
14         /// <summary>
15         /// 在窗口列表中寻找与指定条件相符的第一个子窗口 
16         /// </summary>
17         /// <param name="hwndParent">父窗口句柄</param>
18         /// <param name="hwndChildAfter">子窗口句柄</param>
19         /// <param name="lpszClass">窗口类名</param>
20         /// <param name="lpszWindow">窗口名</param>
21         /// <returns></returns>
22         [DllImport("user32.dll", EntryPoint = "FindWindowEx")]
23         private static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);
24 
25         /// <summary>
26         /// 该函数将指定的消息发送到一个或多个窗口
27         /// </summary>
28         /// <param name="hWnd">接收消息的窗口句柄</param>
29         /// <param name="Msg">指定被发送的消息类型</param>
30         /// <param name="wParam"></param>
31         /// <param name="lParam">发送的消息</param>
32         /// <returns></returns>
33         [DllImport("User32.dll", EntryPoint = "SendMessage")]
34         private static extern int SendMessage(IntPtr hWnd, int Msg, IntPtr wParam, string lParam);
35 
36         //define message type
37         private const int WM_GETTEXT = 0x000D;
38         private const int WM_SETTEXT = 0x000C;
39         private const int WM_CLICK = 0x00F5;
40 
41         public static void Main() 
42         {
43             SearchWindow();
44         }
45 
46         private static void SearchWindow()
47         {
48             //主窗口类型名及窗口名
49             string lpszParentClassName = ""; 
50             string lpszParentWindowName = "Print To File";
51             //主窗口句柄
52             IntPtr ParenthWnd = new IntPtr(0);
53             //子窗口句柄
54             IntPtr EdithWnd = new IntPtr(0);
55 
56             //查到主窗体，得到整个窗体 
57             ParenthWnd = FindWindow(null, lpszParentWindowName);
58             //判断这个窗体是否有效 
59             if (!ParenthWnd.Equals(IntPtr.Zero))
60             {
61                 //得到FileName这个子窗体，并设置其内容 
62                 EdithWnd = FindWindowEx(ParenthWnd, EdithWnd, "Edit", "");
63                 if (!EdithWnd.Equals(IntPtr.Zero))
64                 {
65                     //调用SendMessage方法设置其内容 
66                     SendMessage(EdithWnd, WM_SETTEXT, (IntPtr)0, "你需要输入的文本");
67                 }
68                 //得到OK这个子窗体，并设置其内容 
69                 EdithWnd = FindWindowEx(ParenthWnd, EdithWnd, "Button", "OK");
70                 if (!EdithWnd.Equals(IntPtr.Zero))
71                 {
72                     SendMessage(EdithWnd, WM_CLICK, (IntPtr)0, "");
73                 }
74             }
75         } 
76     }