使用 DataAdapter 和 DataSet 更新数据库

DataAdapter 的 Update 方法：将 DataSet 中的更改解析回数据源。DataSet保存的数据是位于服务器内存里面的原数据库的“副本”。所以用DataSet更新数据的过程就是先对“副本”进行更新，然后在将“原本”更新。

Update 方法会将更改解析回数据源，但是自上次填充 DataSet 以来，其他客户端可能已修改了数据源中的数据。若要使用当前数据刷新 DataSet，请再次使用 DataAdapter 填充 (Fill) DataSet。

EntityAA.cs

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using System;
 2

using System.Data;
 3

using System.Data.SqlClient;
 4

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namespace DataSetAdapter
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{
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    /**//// <summary>
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    /// Summary description for EntityAA.
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    /// </summary>
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    public class EntityAA
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{
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        private string connstr = System.Configuration.ConfigurationSettings.AppSettings["connString"];
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        private SqlConnection conn;
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        private string sql;
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        private SqlDataAdapter adp;
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        private SqlCommandBuilder cb;
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        private DataSet ds;
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        private DataTable dt;
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        public EntityAA()
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{
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            conn = new SqlConnection(connstr);
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            sql = "select * from aa";
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            adp = new SqlDataAdapter(sql,conn);
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            cb = new SqlCommandBuilder(adp);
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            ds = new DataSet();
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            FillDataSet();
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            dt = ds.Tables["table_aa"];
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            dt.PrimaryKey = new DataColumn[]

{dt.Columns["a"]};
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        }
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        private void FillDataSet()
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{
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            conn.Open();
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            adp.Fill(ds,"table_aa");
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            conn.Close();
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        }
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        public DataSet List
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{
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            get 

{return ds;}
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        }
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        public void insert(string c)
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{
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            dt.Columns["a"].AutoIncrement = true;                        
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            DataRow dr = dt.NewRow();
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            dr["c"] = c;
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            dt.Rows.Add(dr);                //添加新行
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            adp.Update(ds,"table_aa");
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        }
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        public void up_date(int ids,string name)
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{
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            DataRow dr = dt.Rows.Find(ids);        //获取由主键值指定的行
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            dr["c"] = name;                        //更新
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            adp.Update(ds,"table_aa");
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        }
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        public void del(int ids)
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{
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            DataRow dr = dt.Rows.Find(ids);        //获取由主键值指定的行
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            dr.Delete();
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            adp.Update(ds,"table_aa");
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        }
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    }
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}
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WebForm1.aspx.cs

using System;

using System.Collections;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Web;

using System.Web.SessionState;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.HtmlControls;

using System.Data.SqlClient;

namespace DataSetAdapter

{

    /**//// <summary>

    /// Summary description for WebForm1.

    /// </summary>

    public class WebForm1 : System.Web.UI.Page

    

{

        protected System.Web.UI.WebControls.Label Label1;

        protected System.Web.UI.WebControls.Label Label2;

        protected System.Web.UI.WebControls.TextBox txt_a;

        protected System.Web.UI.WebControls.TextBox txt_c;

        protected System.Web.UI.WebControls.Button delete;

        protected System.Web.UI.WebControls.Button Button2;

        protected System.Web.UI.WebControls.DataGrid DataGrid1;

        protected System.Web.UI.WebControls.Button Button1;

    

        private void Page_Load(object sender, System.EventArgs e)

        

{

            if(!this.Page.IsPostBack)

                BindGrid();

        }

        Web Form Designer generated code#region Web Form Designer generated code

        override protected void OnInit(EventArgs e)

        

{

            //

            // CODEGEN: This call is required by the ASP.NET Web Form Designer.

            //

            InitializeComponent();

            base.OnInit(e);

        }

        

        /**//// <summary>

        /// Required method for Designer support - do not modify

        /// the contents of this method with the code editor.

        /// </summary>

        private void InitializeComponent()

        

{    

            this.Button1.Click += new System.EventHandler(this.Button1_Click);

            this.delete.Click += new System.EventHandler(this.delete_Click);

            this.Button2.Click += new System.EventHandler(this.Button2_Click);

            this.Load += new System.EventHandler(this.Page_Load);

        }

        #endregion

        private void BindGrid()

        

{

            EntityAA entityaa = new EntityAA();

            DataSet ds = entityaa.List;

            this.DataGrid1.DataSource = ds;

            this.DataGrid1.DataBind();

        }

        private void Button1_Click(object sender, System.EventArgs e)

        

{

            int ids = Int32.Parse(this.txt_a.Text);

            string name = this.txt_c.Text;

            EntityAA entityaa = new EntityAA();

            entityaa.up_date(ids,name);

            BindGrid();

        }

        private void delete_Click(object sender, System.EventArgs e)

        

{

            int ids = Int32.Parse(this.txt_a.Text);

            EntityAA entityaa = new EntityAA();

            entityaa.del(ids);

            BindGrid();

        }

        

        private void Button2_Click(object sender, System.EventArgs e)

        

{

            string c = this.txt_c.Text;

            

            EntityAA entityaa = new EntityAA();

            entityaa.insert(c);

            BindGrid();

        }

        

    }

}