There are two ways to accomplish this textbox effect:
Either using the graphic user interface (GUI); or with code
Using the Graphic User Interface:
Go to: "Properties" Tab; then set the following properties:
However; the best way is to create this by code. See example below.
AutoCompleteStringCollection sourceName = new AutoCompleteStringCollection();
foreach (string name in listNames)
{
sourceName.Add(name);
}
txtName.AutoCompleteCustomSource = sourceName;
txtName.AutoCompleteMode = AutoCompleteMode.Suggest;
txtName.AutoCompleteSource = AutoCompleteSource.CustomSource;