//1 单纯的sql语句 
 string str = "select * from Testtable where '地区字段' like '%" + TextBox1.Text+ "%'";


// 2 查询方法  
public DataTable AllEvent_Select(string dq)
        {
            try
            {
                string str = "select * from Testtable where '地区字段' like '%" + dq+ "%'";
                cmd = SqlHelper.CreateDbCommand(str, conn);
                conn.Open();
                DataTable dt = new DataTable();
                dt.Load(cmd.ExecuteReader());
                return dt;
            }

------解决方案--------------------

C# code

//上面方法少代码，这是全的
 public DataTable AllEvent_Select(string dq)
        {
          try
            {
                string str = "select * from Testtable where '地区字段' like '%" + dq+ "%'";
                cmd = SqlHelper.CreateDbCommand(str, conn);
                conn.Open();
                DataTable dt = new DataTable();
                dt.Load(cmd.ExecuteReader());
                return dt;
            }

            catch (Exception e)
            {

                throw e;
            }
            finally
            {
                conn.Close();
            }
        }