RadDropDownList provides flexible auto-completion options that suggest and append text from choices in the list as the user types. The RadDropDownListAutoCompleteMode property controls auto-complete behavior and can be set to None, Suggest,Append and SuggestAppend:
None
Nothing happens when a user begins to type into the text box portion of the control. If the user types the whole text of an item and presses Enter, the item is selected
Suggest
As the user types an entry into the text box, the drop-down portion of the control is shown, and the displayed items are filtered according to the entered text
Append
As the user types, the next item in the list that matches the user input is automatically appended to the characters the user has already typed. The drop-down list is not shown without the user clicking the arrow.
SuggestAppend
Similar to the Append setting, but the drop-down list is shown and the suggested item is highlighted.
