ASP.NET入门数据篇


            对于网站编程的初学者来说，总是会上网找些源码来看，但久而久之还是停留在改代码的阶段，并不明白怎样去写一个完整的网站程序．有见如此我就开始写这样的文章（c#版），不足之处请批评指正．

数据库连接篇

在WEB项目里看到Web.config配置文件，在configuration这行加入下面代码用于和SQL服务器进行连接

<appSettings><!-- 数据库连接字符串 --><add key="ConnStr" value="Data Source=localhost;database=company;UID=sa;Password=;Persist Security Info=True;" /></appSettings>

数据列表显示篇，如图：





using System;using System.Data;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Web.UI.HtmlControls;

//引用命名空间:SQL托管,配置文件using System.Data.SqlClient;using System.Configuration;

public partial class _Default : System.Web.UI.Page {    protected SqlConnection myconn = new SqlConnection(ConfigurationSettings.AppSettings["ConnectionString"]);    //读取web.config配置文件中的数据库连接字符串,并连接到指定的数据库

    protected void Page_Load(object sender, EventArgs e)    {        if(!IsPostBack)//判断页面是否第一次运行     {

          string strsql="select * from Product";//定义一个数据库的查询字符串                DataSet ds = new DataSet();                myconn.Open();//打开数据库连接                SqlDataAdapter command = new SqlDataAdapter(strsql,myconn);//表示用于填充DataSet 和更新SQL Server 数据库的一组数据命令和一个数据库连接                 command.Fill(ds, "Product");                productList.DataSource = ds.Tables[0].DefaultView;                productList.DataBind();                ds.Clear();          myconn.Close();//关闭数据库连接            } }

    protected void grid_ItemDataBound(object sender, DataGridItemEventArgs e)    {        foreach (System.Web.UI.WebControls.HyperLink link in e.Item.Cells[7].Controls)        {            link.Attributes.Add("onClick", "if (!window.confirm('您真的要删除这条记录吗？')){return false;}");        }    }

}

数据添加篇



protected void btnAdd_Click(object sender, EventArgs e)    {        string ProductId = this.txtProductId.Text;        string CategoryId = this.txtCategoryId.Text;        string Name = this.txtName.Text;        string Description = this.txtDescription.Text;        string Price =this.txtPrice.Text;

        string sql_Exeits = "select * from Product where ProductId='" + ProductId + "'";        SqlCommand cmd_Exeits = new SqlCommand(sql_Exeits, myconn);        myconn.Open();        SqlDataReader rdr = cmd_Exeits.ExecuteReader();        while (rdr.Read())        {            Response.Write("<script language='JavaScript'>");            Response.Write("alert('对不起，该产品编号已经存在！')");            Response.Write("</script>");            this.txtCategoryId.Text = "";            this.txtDescription.Text = "";            this.txtName.Text = "";            this.txtPrice.Text = "";            this.txtProductId.Text = "";            return;        }        rdr.Close();

        string sql_add = "insert into Product(ProductId,CategoryId,Name,Description,Price)values('" + ProductId + "','" + CategoryId + "','" + Name + "','" + Description + "','" + Price + "')";        SqlCommand cmd_add = new SqlCommand(sql_add, myconn);//SqlCommand:表示要对SQL Server数据库执行的一个Transact-SQL语句或存储过程        cmd_add.ExecuteNonQuery();//对连接执行Transact-SQL语句并返回受影响的行数。对于 UPDATE、INSERT 和 DELETE 语句，返回值为该命令所影响的行数。对于所有其他类型的语句，返回值为 -1。如果发生回滚，返回值也为 -1。        myconn.Dispose();        myconn.Close();    }[/CODE

[COLOR=Red]数据显示篇[/COLOR][CODE]protected void Page_Load(object sender, EventArgs e)    {        if (!IsPostBack)        {            string id = Request.Params["id"];            if (id == null || id.Trim() == "")            {                Response.Redirect("default.aspx");                Response.End();            }            else            {                string sql_show = "select * from Product Where ProductId=" + id;                SqlCommand cmd_show = new SqlCommand(sql_show, conn);                conn.Open();                SqlDataReader rd_show = cmd_show.ExecuteReader();//使用SqlDataReader对象读取并返回一个记录集                shows.DataSource = rd_show;//指向数据源                shows.DataBind();//绑定数据                rd_show.Close();//关闭SqlDataReader             }         }    }



数据修改篇



    protected void btnAdd_Click(object sender, EventArgs e)    {        string ProductId = this.lblProductId.Text;        string CategoryId = this.txtCategoryId.Text;        string Name = this.txtName.Text;        string Description = this.txtDescription.Text;        decimal Price = decimal.Parse(this.txtPrice.Text);

        string sql_edit = "update Product set CategoryId='" + CategoryId + "',Name='" + Name + "',Description='" + Description + "',Price='" + Price + "' where ProductId =" + ProductId;        SqlCommand cmd_edit = new SqlCommand(sql_edit, conn);

        conn.Open();        cmd_edit.ExecuteNonQuery();        conn.Close();        Response.Write("<script language=javascript>window.alert('保存成功！')</script>");        Response.Redirect("show.aspx?id=" + ProductId);    }



数据删除篇





protected void Page_Load(object sender, EventArgs e)    {        if (!Page.IsPostBack)        {            string ProductId = Request.Params["id"];            string sql_del = "delete from Product where ProductId=" + ProductId;            SqlCommand cmd_del = new SqlCommand(sql_del, conn);            conn.Open();            cmd_del.ExecuteNonQuery();            conn.Close();            Response.Redirect("default.aspx");        }    }

 



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