使用方法

//如果Type是Button
if (sender.GetType().Name.Equals("Button"))
{
    Button btn = (Button)sender;

    switch (btn.Name)
    {
        case "btn_0":
        case "btn_1":
        case "btn_2":
        case "btn_3":
        case "btn_4":
        case "btn_5":
        case "btn_6":
        case "btn_7":
        case "btn_8":
        case "btn_9":
            if (InputValue.Length >= 20) break;
            checkClear();
            InputValue += btn.Text;
            break;
       ...
    }
}
//如果Type是PictureBox
else
{
    this.Visible = false;
}