AJAX :: Event Handler From Modal Popup Can't Seem To Find A Control That Is On The Modal Popup

I have an Ajax ModalPopupExtender on a page. To summarise. I have a link on a page, when I click the link the modal popup displays. On this modalpopup I've a textbox and an 'ok' and 'cancel' button. I wish to find out what was entered in the textbox when the button is clicked I try this but the value of ((TextBox)button1.Page.FindControl("theTitle")) is null.

if (((TextBox)button1.Page.FindControl("theTitle")).Text == "")
void okButton_Click(object sender, EventArgs e)
{
try
{
//if i try this tt does not compile//The name 'theTitle' does not exist in the current context//if(theTitle.Text == "")//{//}
Button button1 = (Button)sender;
//TextBox theTitle = ((ImageButton)(e.Item.FindControl("theTitle")));
if (((TextBox)button1.Page.FindControl("theTitle")).Text == "")
{
}
else
{
}
}
catch (Exception)
{
}
}