SQLHelper

namespace WpfApplication2
{
   public class SqlHelper
    {
      private static string connStr = ConfigurationManager.ConnectionStrings["ConnStr"].ConnectionString;

        public static int ExecuteNoQuery(string sql)
        { 
            using(SqlConnection conn=new SqlConnection (connStr))
            {
                conn.Open();
                using(SqlCommand cmd=conn.CreateCommand())
                {
                    cmd.CommandText = sql;
                    return cmd.ExecuteNonQuery();
                }
            }
        }
        public static object ExecuteScalar(string sql)
        { 
            using(SqlConnection conn=new SqlConnection (connStr))
            {
                conn.Open();
                using(SqlCommand cmd=conn.CreateCommand())
                {
                    cmd.CommandText = sql;
                    return cmd.ExecuteScalar();
                }
            }
        }
       //用来执行查询结果较少的sql
        public static DataSet ExecuteDataSet(string sql)
        { 
            using(SqlConnection conn=new SqlConnection (connStr))
            {
                conn.Open();
                using(SqlCommand cmd=conn.CreateCommand())
                {
                    cmd.CommandText = sql;
                    SqlDataAdapter adapter = new SqlDataAdapter(cmd);
                    DataSet dataset = new DataSet();
                    adapter.Fill(dataset);
                    return dataset;
                }
            }
        }
    }
}

    private void button2_Click(object sender, RoutedEventArgs e)
        {
            //int a = SqlHelper.ExecuteNoQuery("insert into Table_1 values(5,'bbb',66,'2013-08-08','2013-09-09')");
            //int a=(int)SqlHelper.ExecuteScalar("select count(*) from Table_1");
            //MessageBox.Show(a.ToString());
            DataSet ds = SqlHelper.ExecuteDataSet("select waterwork from Table_1 where id=1 ");
            foreach (DataRow row in ds.Tables[0].Rows)
            {
                string wn = (string)row["waterwork"];
                MessageBox.Show(wn);
            }
        }