private void Form1_Load(object sender, EventArgs e)
{
string[] names ={ "Jhon",
"Joseph",
"Tim",
"Adam",
"Nancy"};
txtAutoComplete.AutoCompleteMode = AutoCompleteMode.Suggest;
txtAutoComplete.AutoCompleteSource=AutoCompleteSource.CustomSource;
AutoCompleteStringCollection lstSource = new AutoCompleteStringCollection();
lstSource.AddRange(names);
txtAutoComplete.AutoCompleteCustomSource = lstSource;
}