autocomplete suggestion textbox

i am using vs2008 nd hav included AjaxCont开发者_如何学编程rolToolKit.DLL required for autocomplete textbox nd included required code like autocompleteextender its not giving any error but my autocomplete textbox is not working

Sample code would helpful, without seeing that, I can only make guesses.

Is the webservice/pagemethod being called? (Put a break point on it and see if it's hit when you type).

Is there an error in the logic of this method?

I think by default, the autocomplete extender fires after 3 characters have been typed, are you hitting this limit?