RadioButtonList OnSelectedIndexChanged

Question

I'm looking for the best way to handle a change of index being selected on a ASP.net RadioButtonList (C# code behind). I have 3 list items. For the first one, I want it to show a hidden asp:textbox on the page, whereas the other 2 will hide the textbox.

//asp.net side
<asp:RadioButtonList ID="_indicatorAckType" runat="server" RepeatDirection="Horizontal"
                enabled="true" OnSelectedIndexChanged="onAckTypeChanged">
    <asp:ListItem Text="None" />
    <asp:ListItem Text="SHOW" />   
    <asp:ListItem Text="HIDE" />
</asp:RadioButtonList>

//code behind
protected void onAckTypeChanged(object sender, EventArgs e)
{
    if (_indicatorAckType.SelectedItem.Text == "SHOW")
        _myTextboxID.Visible = true;
    else
        _myTextboxID.Visible = false;
}

I initially tried using onclick event handlers, but I've been told that ListItem's cannot use onclick events with radio button items. What am I doing wrong here? This does not throw any errors or have any visibly obvious problems. I have tried making onSelectedIndexChanged do nothing except show the textbox and that doesn't work either.

Any help is appreciated! Thanks everyone.

Answer 1

On the RadioButtonList, set the AutoPostBack attribute to true.