How to find checked RadioButton inside Repeater Item?

I have a Repeater control on ASPX-page defined like this:

<asp:Repeater ID="answerVariantRepeater" runat="server"
    onitemdatabound="answerVariantRepeater_ItemDataBound">
    <ItemTemplate>
        <asp:RadioButton ID="answerVariantRadioButton" runat="server"
            GroupName="answerVariants" 
            Text='<%# DataBinder.Eval(Container.DataItem, "Text")%>'"/>
    </ItemTemplate>
</asp:Repeater>

To allow select only one radio button in time I have used a trick form this article.

But now when form is submitted I want to determine which radio button is checked.

I could do this:

RadioButton checkedButton = null;

foreach (RepeaterItem item in answerVariantRepeater.Items)
{
    RadioButton control=(RadioButton)item.FindControl("answerVariantRadioButton");
    if (control.Checked)
    {
        checkedButton = control;
        break;
    }
}

but hope it could be done somehow simplier (maybe via LINQ to objects).

Answers:

Thank you for visiting the Q&A section on Magenaut. Please note that all the answers may not help you solve the issue immediately. So please treat them as advisements. If you found the post helpful (or not), leave a comment & I’ll get back to you as soon as possible.

Method 1

You could always use Request.Form to get the submitted radio button:

var value = Request.Form["answerVariants"];

I think the submitted value defaults to the id of the <asp:RadioButton /> that was selected, but you can always add a value attribute – even though it’s not officially an <asp:RadioButton /> property – and this will then be the submitted value:

<asp:RadioButton ID="answerVariantRadioButton" runat="server"
    GroupName="answerVariants" 
    Text='<%# DataBinder.Eval(Container.DataItem, "Text")%>'"
    value='<%# DataBinder.Eval(Container.DataItem, "SomethingToUseAsTheValue")%>' />

Method 2

Since You are using javascript already to handle the radio button click event on the client, you could update a hidden field with the selected value at the same time.

Your server code would then just access the selected value from the hidden field.

Method 3

I’m pretty sure that the only thing you could use LINQ to Objects for here would be to take the conditions from within the foreach loop and move them to a where clause.

RadioButton checked = 
    (from item in answerVariantRepeater.Items
    let radioButton = (RadioButton)item.FindControl("answerVariantRadioButton")
    where radioButton.Checked
    select radioButton).FirstOrDefault();

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0