c#模糊查询出错

SqlConnection conn = new SqlConnection();
            conn.ConnectionString = "server=LUKE\\SQLEXPRESS;uid=sa;pwd=sa;database=luke";
            conn.Open();
            DataTable dt = new DataTable("resouce");
            dt.Clear();
            SqlDataAdapter adp = new SqlDataAdapter("select * from text1", conn);
            adp.Fill(dt);
            string sql = "select * from text1 where bh like %"+textBox1.Text+"%";
            SqlCommand command = new SqlCommand(sql, conn);
            SqlDataAdapter ad = new SqlDataAdapter();
            ad.SelectCommand = command;
            ad.Fill(dt);
            dt.Clear();
            dataGridView1.DataSource = dt.DefaultView;
我在textbox1中输入查询数字 2 提示出错