C#中如何判断鼠标和键盘同时按下？
不是设置两个bool变量，u批以后变false

[解决办法]
private void Form1_MouseDown(object sender, MouseEventArgs e)
{
if (Control.ModifierKeys == Keys.Alt && e.Button == MouseButtons.Left)
MessageBox.Show( "Alt+Left ");
}

[解决办法]
GetKeyState