C#实现的三种方式实现模拟键盘按键

江南才子

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);