Update Panel error: Control with the ID “xxx” could not be found in the UpdatePanel

Question

I have a composite drop down calendar user control that consists of a textbox and and calendar image and a validation control. I expose a property called \"TextBox\" on the

Answer 1

According what I understand the textbox is embedded on User Control dtmDateFirstEntry. You CANNOT use directly a control contained by a user control. The user control MUST expose the events of his child controls if you want to use them as triggers.

DateChanged would be an event exposed by dtmDateFirstEntry. Do you know how to do this?