c#文本框记忆功能

          var source = new AutoCompleteStringCollection();
            source.AddRange(new string[]
                    {
                        "110",
                        "119",
                        "120",
                        "112",
                        "10010",
                        "10086"   
                    });
          
            textBox1.AutoCompleteCustomSource = source;
            textBox1.AutoCompleteMode = AutoCompleteMode.SuggestAppend;
            textBox1.AutoCompleteSource = AutoCompleteSource.CustomSource;



//form_Load