ADO.NET 2.0 Dataset和Datatable 新功能新特性

发布时间：2020-12-15 21:11:29 所属栏目：asp.Net 来源：网络整理

导读：p style="FONT-SIZE: 10pt"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： p style="FONT-SIZE: 10pt"DataSet ds = new DataSet(); p style="FONT-SIZE: 10pt"??????????? ds.Tables.Add("BigTable");???????

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;

（编辑：李大同）

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