c# Findwindow sendMessage

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using System.Windows.Forms;
namespace TencentMsg
{

   public  class Win32API
    {

       [DllImport("user32.dll", EntryPoint = "FindWindow")]
       private static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);

       [DllImport("user32.dll", EntryPoint = "SendMessageA")]
       public static extern int SendMessage(IntPtr hwnd, int wMsg, IntPtr wParam, IntPtr lParam);
       [DllImport("user32.dll", EntryPoint = "SendMessageA")]
       public static extern int SendMessage(IntPtr hwnd, int wMsg, int wParam, int lParam);

       ///<summary>
       /// 设置指定窗口为当前活动窗口
       ///</summary>
       ///<param name="hWnd">窗口句柄</param>
       [DllImport("User32.DLL")]
       private static extern bool SetForegroundWindow(IntPtr hWnd);

       ///<summary>
       /// 向指定窗口发送字符串
       ///</summary>
       [DllImport("User32.dll", EntryPoint = "SendMessage")]
       private static extern int SendMessage(IntPtr hWnd, int Msg, IntPtr wParam, string lParam);

       [DllImport("shell32.dll")]
       public static extern int ShellExecute(IntPtr hwnd, StringBuilder lpszOp, StringBuilder lpszFile, StringBuilder lpszParams, StringBuilder lpszDir, int FsShowCmd);
       [DllImport("user32.dll")]
       private static extern bool EnumWindows(WNDENUMPROC lpEnumFunc, int lParam);
       [DllImport("user32.dll", CharSet = CharSet.Auto)]
       public static extern int SendMessage(IntPtr hWnd, int msg, int wParam, string lparam);
       [DllImport("user32.dll", EntryPoint = "FindWindow", SetLastError = true)]//查找窗口
       private static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
       [DllImport("user32.dll")]
       public static extern int GetWindowText(IntPtr hWnd, StringBuilder lpString, int nMaxCount);
       [DllImport("user32.dll")]
       private static extern int GetWindowTextW(IntPtr hWnd, [MarshalAs(UnmanagedType.LPWStr)]StringBuilder lpString, int nMaxCount);
       [DllImport("user32.dll")]
       private static extern int GetClassNameW(IntPtr hWnd, [MarshalAs(UnmanagedType.LPWStr)]StringBuilder lpString, int nMaxCount);
       private delegate bool WNDENUMPROC(IntPtr hWnd, int lParam);
       static IntPtr Game;

      const int BM_CLICK = 0xF5;   

  public static  bool FindWind(string sTitle){
   IntPtr hwnd = FindWindow(null, sTitle);
   return (hwnd != IntPtr.Zero) ;

  }

    public  class WindowInfo {

         public IntPtr hWnd;
         public string szClassName;
         public string szWindowName;

    }

  //寻找系统的全部窗口
 public  static WindowInfo[] GetAllDesktopWindows()
  {
      List<WindowInfo> wndList = new List<WindowInfo>();
      EnumWindows(delegate(IntPtr hWnd, int lParam)
      {
          WindowInfo wnd = new WindowInfo();
          StringBuilder sb = new StringBuilder(256);
          //get hwnd
          wnd.hWnd = hWnd;
          //get window name
          GetWindowTextW(hWnd, sb, sb.Capacity);
          wnd.szWindowName = sb.ToString();
          //get window class
          GetClassNameW(hWnd, sb, sb.Capacity);
          wnd.szClassName = sb.ToString();
          //Console.WriteLine("Window handle=" + wnd.hWnd.ToString().PadRight(20) + " szClassName=" + wnd.szClassName.PadRight(20) + " szWindowName=" + wnd.szWindowName);
          //add it into list
          if (wnd.szClassName == "TXGuiFoundation" && wnd.szWindowName=="查找")
          {
              wndList.Add(wnd);
          }

          return true;
      }, 0);
      return wndList.ToArray();
  }

public static  bool FindSearchWind(){

   IntPtr maindHwnd = FindWindow("TXGuiFoundation", "");  

    if(maindHwnd != IntPtr.Zero){

         IntPtr childHwnd = FindWindowEx(maindHwnd, IntPtr.Zero, null, "登录");
        if (childHwnd != IntPtr.Zero)
        {
            SendMessage(childHwnd, BM_CLICK, 0, 0);
        }
        else
        {
            MessageBox.Show("没有找到子窗口");
        }   

    }

   return (maindHwnd != IntPtr.Zero) ;

  }

    }
}

　　

more: https://www.cnblogs.com/tary2017/articles/8031782.html