1         private void Form1_Load(object sender, EventArgs e)//这个是调用方法  2         {
    3             btnVal0.Click += new EventHandler(btnVal_Click);  4             btnVal1.Click += new EventHandler(btnVal_Click);  5             btnVal2.Click += new EventHandler(btnVal_Click);  6             btnVal3.Click += new EventHandler(btnVal_Click);  7             btnVal4.Click += new EventHandler(btnVal_Click);  8             btnVal5.Click += new EventHandler(btnVal_Click);  9             btnVal6.Click += new EventHandler(btnVal_Click); 10             btnVal7.Click += new EventHandler(btnVal_Click); 11             btnVal8.Click += new EventHandler(btnVal_Click); 12             btnVal9.Click += new EventHandler(btnVal_Click); 13         } 14 15         private void btnVal_Click(object sender, EventArgs e)//此为方法 16         {
   17             Button btn =(Button)sender;//sender转换成Button 18             if (num1 == null) 19             {
   20                 num1 = Convert.ToInt32(btn.Text); 21             } 22             else 23             {
   24                 num2 = Convert.ToInt32(btn.Text); 25             } 26             tbshow.Text = btn.Text; 27          28         }