Thank you very much for the response. I am sorry for not making my question clear. Here is what I would like to implement Autocomplete/Autosuggest feature when user perform the location search. I was able to use QueryAsync to get the list of addresses or streetname from the feature in geodatabase then bind to ComboBox that has Autocomplete feature. I found this way had an issue because of the hit with memory increasing in the way up to 400MB. Is there a better way to implement it?
Unfortunately we don't have any specific auto-complete functionality at the moment - but here's an example of how you could implement it in a WPF app: http://www.arcgis.com/home/item.html?id=21a58d089764402e90ce127894dec94e
It's built against the previous WPF SDK but should give you an idea of how you could implement similar functionality in the .NET SDK.http://developersdev.arcgis.com/net/sample-code/