[asp.net] Set Radiobuttonlist Selected from Codebehind

Hey I have a radiobuttonlist and trying to set one of the radiobuttons to selected based on a session variable but proving impossible.

<asp:radiobuttonlist id="radio1" runat="server" AutoPostBack="True" OnSelectedIndexChanged="RadioButtonList1_SelectedIndexChanged">
   <asp:listitem id="option1" runat="server" value="All"/>
   <asp:listitem id="option2" runat="server" value="1" />
   <asp:listitem id="option3" runat="server" value="2" />
</asp:radiobuttonlist> 

I.e How can I set option2 to selected in code behind ?

var rad_id = document.getElementById('<%=radio_btn_lst.ClientID %>');
var radio = rad_id.getElementsByTagName("input");
radio[0].checked = true;

//this for javascript in asp.net try this in .aspx page

// if you select other radiobutton increase [0] to [1] or [2] like this

The best option, in my opinion, is to use the Value property for the ListItem, which is available in the RadioButtonList.

I must remark that ListItem does NOT have an ID property.

So, in your case, to select the second element (option2) that would be:

// SelectedValue expects a string
radio1.SelectedValue = "1"; 

Alternatively, yet in very much the same vein you may supply an int to SelectedIndex.

// SelectedIndex expects an int, and are identified in the same order as they are added to the List starting with 0.
radio1.SelectedIndex = 1; 

We can change the item by value, here is the trick:

radio1.ClearSelection();
radio1.Items.FindByValue("1").Selected = true;// 1 is the value of option2

Try this option:

radio1.Items.FindByValue("1").Selected = true;