C# 确保在按住键时只执行一次语句。

如果按住numpad上的5键，它将继续在KeyDown事件处理程序中执行一条语句。即使我按下键，如何确保语句只执行一次

private void form_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
   if (e.KeyCode == Keys.NumPad5)
   {
        dados.enviar("f"); //I want this to run only once!
   }
}

谢谢你的关注

private void form_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
   if (e.KeyCode == Keys.NumPad5)
   {
        dados.enviar("f"); //I want this to run only once!
   }
}

---

您可以在向下键上设置标志，在向上键上重置标志

private void form_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
   if (e.KeyCode == Keys.NumPad5)
   {
        dados.enviar("f"); //I want this to run only once!
   }
}

    private bool isPressed = false;
    public Form1()
    {
        InitializeComponent();
    }

    private void Form1_KeyDown(object sender, KeyEventArgs e)
    {
        if(e.KeyCode == Keys.B && !isPressed )
        {
            isPressed = true;
            // do work
        }
    }

    private void Form1_KeyUp(object sender, KeyEventArgs e)
    {
        if (isPressed )
            isPressed = false;
    }

---

您应该使用IsRepeat标志检查是否是第一次按下按键

private void form_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
   if (e.KeyCode == Keys.NumPad5)
   {
        dados.enviar("f"); //I want this to run only once!
   }
}

if (e.KeyCode == Keys.NumPad5 && !e.IsRepeat)