detect a postback from a radiobutton list

Question

I am trying to detect a postback from Radiobutton list. I am trying to use following code:

If Page.Request.Params.Get("__EVENTTARGET") = optDownload.UniqueID.ToString Then

But Page.Request.Params.Get("__EVENTTARGET") returns

"ctl00$ContentPlaceHolder1$pnlBarAccounts$i0$i2$i0$CHChecking$Acct1$optDownload$4"

And optDownload.UniqueID.ToString returns

"ctl00$ContentPlaceHolder1$pnlBarAccounts$i0$i2$i0$CHChecking$Acct1$optDownload"

There is a difference in last 2 characters, how do I detect a postback from Radiobutton list?

Answer 1

Doesn't the RadioButtonList have an event you could listen to?

Answer 2

The $4, I'm assuming, relates to the index of the selection radio options.

Just use the string contains function, i.e.

if (Page.Request.Params.Get("__EVENTTARGET").Contains(optDownload.UniqueID.ToString))
{
   // Radio list caused the postback
}

Anyway, that's very bad. You should be listening for the event on the RadioButtonList. Hook into the SelectedIndexChange event.

RadioButtonList list = new RadioButtonList();
list.SelectedIndexChanged += new EventHandler(list_SelectedIndexChanged);

protected void list_SelectedIndexChanged(object sender, EventArgs e)
{
   // Your radio button fired the postback
}

That'll work, but it sounds like you're fixing the wrong problem for whatever reason you need to know if the list caused a postback.