winform中textbox提示框

private void Form1_Load(object sender, EventArgs e)

{

AutoCompleteStringCollection strings = new AutoCompleteStringCollection();

strings.Add("A1");//不区分大小写

strings.Add("A2");

strings.Add("Aas");

strings.Add("B1");

strings.Add("Beijing");

strings.Add("bb-cims");

textBox1.AutoCompleteCustomSource = strings;

textBox1.AutoCompleteSource = AutoCompleteSource.CustomSource;

textBox1.AutoCompleteMode = AutoCompleteMode.Suggest;

}