How to set checked value for a radio input tag using ASP.Net?

Question

I have this radio tag:

<input name="phoneRadio" class="phoneRadio" id="rbDefaultPhone" 
    type="radio" checked="<%# GetIsChecked(Eval("IsDefault")) %>"/>

in a repeater and GetIsChecked is a c# function which return bool value, my problem that its not affecting the checked value of the radio button the right way, Any one know how to fix that?

Answer 1

Just having the checked attribute on the input is enough to make it checked. In HTML, you just need to have checked in there, in XHTML, it should be checked="checked", but either way, you'll want to exclude the whole attribute if it isn't checked.

That is, GetIsChecked should (be renamed and) return either "checked='checked'" or String.Empty. You will then call it just in the input tag itself, not as the value for the checked attribute (which you should remove). It'll look something like this:

<input name="phoneRadio" class="phoneRadio" id="rbDefaultPhone" type="radio" <%# GetChecked(Eval("IsDefault"))%> />

 

protected string GetChecked(object isDefault)
{
    return (bool)isDefault ? "checked='checked'" : string.Empty;
}

Answer 2

Bdukes's answer is correct. Before coming to this post, I spent lot of time in trying to figure out how to return checked=checked but

checked
checked=""
checked="checked"

are equivalent.

Considering 'IsDefault' returns bool,works well in all modern browsers.

<input name="phoneRadio" class="phoneRadio" id="rbDefaultPhone"  type="radio" 
 checked='<%#Eval("IsDefault")%>'

Check this for more explanation.