委托

public delegate void MyDelegate(object sender, EventArgs e);

    protected void Page_Load(object sender, EventArgs e)
    {
        MyDelegate md = new MyDelegate(Button1_Click);
        //md(Button1, null);
        md(Button1, new System.EventArgs());
        //MyDelegate md1 = new MyDelegate(DropDownList1_SelectedIndexChanged);
        //md1(DropDownList1, null);

    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        Response.Write(Button1.Text + "按钮被点击");
    }
    protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    {
        Response.Write("下拉选项值被改变被调用");
    }