学步园

        private void Form1_Load(object sender, EventArgs e)
        {
            //自动完成字符串的集合
            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;
        }

这样你在textBox1中输入A或者a时就会在下拉框中显示出A1...A2...Aas