How Can I Bind Field To Label

//Put this code in Combobox selected index change event

      DataTable dt = new DataTable();
      using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionName"].ConnectionString))
      {
          using (SqlCommand cmd = new SqlCommand("select Mark from TableName where Name="+ ComboBox.SelectedValue, con))
          {
              con.Open();
              SqlDataAdapter da = new SqlDataAdapter(cmd);
              da.Fill(dt);

              lblMark.Text = Convert.ToString(dt.Rows["Mark"]);

              con.Close();
              con.Dispose();
              cmd.Dispose();
          }
      }