ADO.NET 2.0 Dataset和Datatable 新功能新特性

1.新的索引引擎更快的执行效率
   下面这段代码在2003中需要157秒，在2005中只要11秒就可以完成：

DataSet ds  =   new  DataSet();

            ds.Tables.Add( " BigTable " );
            ds.Tables[ 0 ].Columns.Add( " ID " , Type.GetType( " System.Int32 " ));
            ds.Tables[ 0 ].Columns[ " ID " ].Unique  =   true ;
            ds.Tables[ 0 ].Columns.Add( " Value " , Type.GetType( " System.Int32 " ));

            Cursor.Current  =  Cursors.WaitCursor;

            DateTime datBegin  =  DateTime.Now;

            Random rand  =   new  Random();
             int  i, intValue;
            DataRow dr;

             for  (i  =   1 ; i  <=   500000 ; i ++ )
             {
                try
                {
                    intValue = rand.Next();

                    dr = ds.Tables[0].NewRow();

                    dr["ID"] = intValue;
                    dr["Value"] = intValue;

                    ds.Tables[0].Rows.Add(dr);
                }
                catch { }
            }

            Cursor.Current  =  Cursors.Default;

            MessageBox.Show( " Elapsed Time:  "   +  (DateTime.Now  -  datBegin).Seconds.ToString());
            MessageBox.Show( " count =  "   +  ds.Tables[ 0 ].Rows.Count.ToString());

2.Dataset可以序列化为二进制文件

  string  connstr  =   " server=(local);database=northwind;integrated security=true;async=true " ;

            DataSet ds  =   new  DataSet();
            SqlDataAdapter dadpt  =   new  SqlDataAdapter( " select * from [order details] " , connstr);
            dadpt.Fill(ds);

            BinaryFormatter bf  =   new  BinaryFormatter();
            FileStream fs  =   new  FileStream( @" c:/xml1.txt " ,FileMode.OpenOrCreate);

            ds.RemotingFormat = SerializationFormat.Binary;

            bf.Serialize(fs,ds);     

3.更独立的Datatable
  DataTable Write XML

  string  connstr  =   " server=(local);database=northwind;integrated security=true;async=true " ;
            SqlDataAdapter dadpt  =   new  SqlDataAdapter( " select * from [order details] " , connstr);
            DataTable dt  =   new  DataTable( " Customer " );
            dadpt.Fill(dt);

            dt.WriteXml( @" c:/DataTable.xml " , true );
            dt.WriteXmlSchema( @" c:/DataTableSchema.xml " );

   DataTable Read XML

 StreamReader sr  =   new  StreamReader( @" C:/DataTableSchema.xml " );

            DataTable dt  =   new  DataTable();
            dt.ReadXmlSchema(sr);

            dt.ReadXml( new  StreamReader( @" c:/dataTable.xml " ));

             this .dataGridView1.DataSource  =  dt;

    DataTable Merge

  string  connstr  =   " server=(local);database=northwind;integrated security=true;async=true " ;
            SqlDataAdapter dadpt  =   new  SqlDataAdapter( " select * from customers " , connstr);
            DataTable dt  =   new  DataTable( " Customer " );
            dadpt.Fill(dt);

            SqlDataAdapter dadpt1  =   new  SqlDataAdapter( " select * from customers " , connstr);
            DataTable dt1  =   new  DataTable( " Customer1 " );
            dadpt1.Fill(dt1);

            dt.Merge(dt1);

             this .dataGridView1.DataSource  =  dt;

  DataTable Load DataReader

  string  connstr  =   " server=(local);database=northwind;integrated security=true;async=true " ;
            SqlConnection conn  =   new  SqlConnection(connstr);
            conn.Open();
            SqlCommand cmd  =   new  SqlCommand( " select * from [order details] " , conn);
            SqlDataReader dr  =  cmd.ExecuteReader();

            DataTable dt  =   new  DataTable( " Customer " );
            dt.Load(dr);

             this .dataGridView1.DataSource  =  dt;