winform textbox自动检索；textbox智能选择；textbox自动模糊查询； textbox AutoCompleteMode

    #region 
            AutoCompleteStringCollection cs = new AutoCompleteStringCollection();
            this.textBox1.AutoCompleteMode = AutoCompleteMode.Suggest;
            this.textBox1.AutoCompleteSource = AutoCompleteSource.CustomSource;
            this.textBox1.AutoCompleteCustomSource = cs;
            cs.Clear();
            string sql = "select colum1 from tablename where colum1 is not null";
            DataTable dt = objFrmMain.ObjCDataOperation.MyDB.OpenSQL(sql);
            if (dt != null && dt.Rows.Count > 0)
            {

                foreach (DataRow dr in dt.Rows)
                {
                    cs.Add(dr["colum1"].ToString());
                }

            }

            #endregion

把以上内容放到load里面，适用于数据量小的查询