c#中DataList的问题

for (int i = 0; i < DataList1.Items.Count; i++)
｛
RadioButtonList RBL=(RadioButtonList)Datalist1.items[i].FindControl("RadioButtonList1");
String aaa=RBL.Selecteditem.text.tostring();

}

我在做在线考试系统的时候遇到同样的问题，最后有办法解决，不过我不是用RadioButtonList,我是用了四个RadioButton，因为我做的是选择题，所以有四个选项，分别用了四个RadioButton来供选择：
for (int i = 0; i < DataList1.Items.Count; i++)
｛
CheckBox tm1 = (CheckBox)DataList1.Items[i].FindControl("RadioButton1");
if (tm1.Checked)
{
//RadioButton1就被选中了
}
CheckBox tm2 = (CheckBox)DataList1.Items[i].FindControl("RadioButton2");

if (tm2.Checked)
{
//RadioButton2就被选中了
}

CheckBox tm3 = (CheckBox)DataList1.Items[i].FindControl("RadioButton3");

if (tm3.Checked)
{
//RadioButton3就被选中了
}

CheckBox tm4 = (CheckBox)DataList1.Items[i].FindControl("RadioButton4");
if (tm4.Checked)