c#实现多个按键同时按下检测

    下面的方法在C#中实现了三个按键同时按下的检测，更多按键按下同样可以检测。

    在PreviewKeyDown事件中检测按键按下：

        private void Form1_PreviewKeyDown(object sender, PreviewKeyDownEventArgs e)
        {
            switch (e.KeyValue)
            {
                case 'A':
                    if (key1down == false)
                        MessageBox.Show("A down");
                    key1down = true;             // 按键"A"按下此标志为true，直到放开
                    break;
                case 'B':
                    if (key2down == false)
                        MessageBox.Show("B down");
                    key2down = true;            // 按键"B"按下此标志为true，直到放开
                    break;
                case 'C':
                    if (key3down == false)
                        MessageBox.Show("C down");
                    key3down = true;            // 按键"C"按下此标志为true，直到放开
                    break;
            }
        }

 

    在KeyUp事件中检测按键放开：
        private void Form1_KeyUp(object sender, KeyEventArgs e)
        {
            switch (e.KeyValue)
            {
                case 'A':
                        MessageBox.Show("A up");
                    key1down = false;           // 按键"A"放开此标志为false
                    break;
                case 'B':
                        MessageBox.Show("B up");
                    key2down = false;          // 按键"A"放开此标志为false
                    break;
                case 'C':
                        MessageBox.Show("C up");
                    key3down = false;          // 按键"A"放开此标志为false
                    break;
            }
        }