ADO.NET 2.0 Dataset和Datatable 新功能新特性-.NET教程,Asp.Net开发

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;