这个问题应该怎么解决?

Question

public void Arrange()
             {                 int r=15;
               int c=16;
               for (int i=0;i<r;i++)
                {
                   for (int j=0;j<c;j++)
                  {              
                     Button btn=new Button();
                     btn.Click += Button7_Click; 
                     btn.ID=(i+1).ToString()+"-"+(j+1).ToString();
                     btn.Text = "";
                     btn.Width = 40;
                     btn.Height = 30;
                     btn.ToolTip=(i + 1).ToString() + "-" + (j + 1).ToString();
                     Panel1.Controls.Add(btn);                     }
               }
}public void Button7_Click(object sender, EventArgs e)
        {       btn.BorderColor = System.Drawing.Color.Green;        }当点击了页面上动态生成的按钮后,如何让被点击的按钮的边框颜色变成绿色?

Answer 1

(sender as Button).BorderColor = System.Drawing.Color.Green;