The target 'ctl100$ctl100$PageContent$PageContent$ctl11$drpdwnEmail1' for the callback could not be found or did not implement ICallbackEventHandler
I am thinking it is because the user control that contains the above ComboBox is added dynamically, and when the OnItemsRequested handler is fired on the combobox, it no longer exists. The solutions I have found on this site say to make sure to add the control each time OnPageLoad. However, this isn't realistic because parameters are passed to the control depending on which row of a Repeater we are in....
I am not sure in this example how to get past this error - I need to load the control in the manner I am loading it and can't do it each time a postback happens, and I need to populate the email dropdown server-side because there are about 100,000 email addresses so I want them to start typing before they see anything...
Any help would be greatly appreciated!!!