如果检查出正确答案，则添加1

Question

例如，我有两个单选按钮列表：

<asp:RadioButtonList ID="rbl1" runat="server" OnSelectedIndexChanged="rbl1_SelectedIndexChanged" AutoPostBack="True" >
<asp:ListItem Value="1">&nbsp;1</asp:ListItem>
<asp:ListItem Value="2">&nbsp;2</asp:ListItem>
<asp:ListItem Value="3">&nbsp;3</asp:ListItem>
<asp:ListItem Value="4">&nbsp;4</asp:ListItem>
</asp:RadioButtonList>
<asp:RadioButtonList ID="rbl2" runat="server" AutoPostBack="True" OnSelectedIndexChanged="rbl2_SelectedIndexChanged"  >
<asp:ListItem Value="1">&nbsp;1</asp:ListItem>
<asp:ListItem Value="2">&nbsp;2</asp:ListItem>
<asp:ListItem Value="3">&nbsp;3</asp:ListItem>
<asp:ListItem Value="4">&nbsp;4</asp:ListItem>
</asp:RadioButtonList>

protected void rbl1_SelectedIndexChanged(object sender, EventArgs e)
{
    if (rbl1.SelectedIndex == 1)
    {

        Label1.Text = "Correct Answer.";
    }
    else
    {

        Label1.Text = "Incorect";

    }

}
protected void rbl2_SelectedIndexChanged(object sender, EventArgs e)
{
    if (rbl2.SelectedIndex == 0)
    {


        Label2.Text = "Correct Answer";
    }
    else
    {

        Label2.Text = "Incorect";

    }

我想如果rbl1 selectedindex = 1则向标签（如Lable3）添加1个值，以显示rbl2 selectedindex = 0时，再次将label3中先前的分数加1。

请帮助我，谢谢。