模拟按键在.Net中有三种方式实现。

第一种方式：System.Windows.Forms.SendKeys 

                     组合键：Ctrl = ^ 、Shift = + 、Alt = %

模拟按键：A

        private void button1_Click(object sender, EventArgs e)
        {
            textBox1.Focus();
            SendKeys.Send("{A}");
        }

模拟组合键：CTRL + A

        private void button1_Click(object sender, EventArgs e)
        {
            webBrowser1.Focus();
            SendKeys.Send("^{A}");
        }

SendKeys.Send // 异步模拟按键(不阻塞UI)

SendKeys.SendWait // 同步模拟按键(会阻塞UI直到对方处理完消息后返回)

第二种方式：keybd_event

模拟按键：A

        [DllImport("user32.dll", EntryPoint = "keybd_event", SetLastError = true)]
        public static extern void keybd_event(Keys bVk, byte bScan, uint dwFlags, uint dwExtraInfo);

        private void button1_Click(object sender, EventArgs e)
        {
            textBox1.Focus();
            keybd_event(Keys.A, 0, 0, 0);
        }

模拟组合键：CTRL + A

        public const int KEYEVENTF_KEYUP = 2;

        private void button1_Click(object sender, EventArgs e)
        {
            webBrowser1.Focus();
            keybd_event(Keys.ControlKey, 0, 0, 0);
            keybd_event(Keys.A, 0, 0, 0);
            keybd_event(Keys.ControlKey, 0, KEYEVENTF_KEYUP, 0);
        }

上面两种方式都是全局范围呢，现在介绍如何对单个窗口进行模拟按键

模拟按键：A / 两次

        [DllImport("user32.dll", EntryPoint = "PostMessageA", SetLastError = true)]
        public static extern int PostMessage(IntPtr hWnd, int Msg, Keys wParam, int lParam);

        public const int WM_CHAR = 256;

        private void button1_Click(object sender, EventArgs e)
        {
            textBox1.Focus();
            PostMessage(textBox1.Handle, 256, Keys.A, 2);
        }

模拟组合键：CTRL + A

       如下方式可能会失效，所以最好采用上述两种方式

        public const int WM_KEYDOWN = 256;
        public const int WM_KEYUP = 257;

        private void button1_Click(object sender, EventArgs e)
        {
            webBrowser1.Focus();
            keybd_event(Keys.ControlKey, 0, 0, 0);
            keybd_event(Keys.A, 0, 0, 0); 
            PostMessage(webBrowser1.Handle, WM_KEYDOWN, Keys.A, 0);
            keybd_event(Keys.ControlKey, 0, KEYEVENTF_KEYUP, 0);

C#实现的三种方式实现模拟键盘按键