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
 1using System;
 2using System.Data;
 3using System.Data.SqlClient;
 4
 5namespace DataSetAdapter
 6{
 7    /// <summary>
 8    /// Summary description for EntityAA.
 9    /// </summary>

10    public class EntityAA
11    {
12        private string connstr = System.Configuration.ConfigurationSettings.AppSettings["connString"];
13        private SqlConnection conn;
14
15        private string sql;
16
17        private SqlDataAdapter adp;
18        private SqlCommandBuilder cb;
19
20        private DataSet ds;
21        private DataTable dt;
22
23        public EntityAA()
24        {
25            conn = new SqlConnection(connstr);
26            sql = "select * from aa";
27
28            adp = new SqlDataAdapter(sql,conn);
29            cb = new SqlCommandBuilder(adp);
30
31            ds = new DataSet();
32
33            FillDataSet();
34
35            dt = ds.Tables["table_aa"];
36
37            dt.PrimaryKey = new DataColumn[]{dt.Columns["a"]};
38        }

39        
40        private void FillDataSet()
41        {
42            conn.Open();
43            adp.Fill(ds,"table_aa");
44            conn.Close();
45        }

46
47        public DataSet List
48        {
49            get {return ds;}
50        }

51
52        public void insert(string c)
53        {
54            dt.Columns["a"].AutoIncrement = true;                        
55
56            DataRow dr = dt.NewRow();
57            dr["c"= c;
58            dt.Rows.Add(dr);                //添加新行
59
60            adp.Update(ds,"table_aa");
61
62        }

63
64        public void up_date(int ids,string name)
65        {
66            DataRow dr = dt.Rows.Find(ids);        //获取由主键值指定的行
67            dr["c"= name;                        //更新
68
69            adp.Update(ds,"table_aa");
70        }

71
72        public void del(int ids)
73        {
74            DataRow dr = dt.Rows.Find(ids);        //获取由主键值指定的行
75            dr.Delete();
76
77            adp.Update(ds,"table_aa");
78
79        }

80
81
82    }

83}

84

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();
        }


        
#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();
        }


        



    }

}

posted @ 2005-05-18 14:08  Ready!  阅读(...)  评论(...编辑  收藏
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