Showing autocomplete suggestion on Cell begin edit C# winforms

I use C#.net 2010 and windows form. I have a Datagridview and i want to show the auto complete for the cell when a cell is in edit mode. I show the auto complete suggestion using the code below:

TextBox txt=e.Control as TextBox;
txt.AutoCompleteMode=AutoCompleteMode.Suggest;
txt.AutoCompleteSource=AutoCompleteSource.CustomSource;
AutoCompleteStringCollection clction=new AutoCompleteStringCollection();
txt.AutoCompleteCustomSource=clction;

clction.add("this string ");

the autocomplete works fine but I want to show the auto complete value for a Column each time. the auto complete text is too long and if user starts to type different chars the auto complete goes away. but i want to show the suggestion in a way that is not related to the typed text. First i thought i should put a textbox element and change the position of element each time the user starts typing but it did not worked good for my purpose. So what are the alternatives here?