在网上看到有人问C#中模拟鼠标点击按钮的帖子，在VB中用API实现的代码网上不少，可用C#写的基本就没有了，在这里简单写个事例。

1、首先建一个Demo项目。只有一个表单，标题是"Demo"。里面放一个按钮Button1，Text设置为"Click Me"。编译成exe。做事例用，这个代码就不用贴出来了吧 呵呵。

2、新建项目，添加表单，拖个按钮。代码如下：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.Diagnostics;

namespace ClickButton_SendMessage
{
    public delegate bool CallBack(IntPtr hwnd, int lParam);

    
    public partial class frmMain : Form
    {

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        static extern IntPtr FindWindow(string strClass, string strWindow);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        static extern IntPtr EnumChildWindows(IntPtr hWndParent, CallBack lpEnumFunc, int lParam);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        static extern int GetWindowRect(IntPtr hwnd,RECT lpRect);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        static extern int SetCursorPos(int x,int y);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        static extern int SetForegroundWindow(IntPtr hwnd);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        static extern void mouse_event(int dwFlags,int dx,int dy,int cButtons, int dwExtraInfo);
        public const int MOUSEEVENTF_LEFTDOWN = 0x2;
        public const int MOUSEEVENTF_LEFTUP = 0x4;

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        static extern int GetWindowText(IntPtr hwnd, string lpString, int cch);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        static extern int GetWindowTextLength(IntPtr hwnd);

        public struct RECT
        {
            public int Left;
            public int Top;
            public int Right;
            public int Bottom;
        }

        public struct POINT
        {
            public int x;
            public int y;
        }

        public static int nCount;

        public frmMain()
        {
            InitializeComponent();
            
        }

        public static bool EnumWindowsProc(IntPtr h, int lParam)
        {

            string strText=new string((char)0,255);
            RECT hRect=new RECT();

            nCount = nCount + 1;
            
            int Ret=0;
            
            Ret = GetWindowTextLength(h);
            string sSave = new string((char)9, Ret);
            GetWindowText(h, sSave, Ret + 1);
            if(sSave.IndexOf("Click Me",0) > -1)
            {
                //GetWindowRect(h, hRect);
                //SetCursorPos((hRect.Left + hRect.Right) / 2, (hRect.Top + hRect.Bottom) / 2);
                SetCursorPos(200, 160);//这是用Spy++直接获取的，VS都带这个工具
                SetForegroundWindow(h);
                mouse_event(MOUSEEVENTF_LEFTDOWN | MOUSEEVENTF_LEFTUP, 0, 0, 0, 0);
                return false;
            }
            return true;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            IntPtr h;
            string strName = "Demo";
            h = FindWindow(null, strName);
            Debug.Print(h.ToString());
            if (h.ToInt32() != 0)
            {
                CallBack myCallBack = new CallBack(frmMain.EnumWindowsProc);
                EnumChildWindows(h, myCallBack, 0);
            }
        }
    }
}
3、如果想不停的点击 加个Timer不停点击。 或者加个变量IsLogin = FindWindow(null,"登陆成功后的标题 或 登录失败提示标题")
另外，只有登录按钮所在的窗体在激活时才能点中。 可以用ShowWindow()先激活窗体，然后再进行点击操作。