ASP.NET入門資料篇

對於網站編程的初學者來說，總是會上網找些源碼來看，但久而久之還是停留在改代碼的階段，並不明白怎樣去寫一個完整的網站程式．有見如此我就開始寫這樣的文章（c#版），不足之處請批評指正．

資料庫連接篇

在WEB項目裡看到Web.config設定檔，在configuration這行加入下面代碼用於和SQL伺服器進行串連

<appSettings>
<!-- 資料庫連接字串 -->
<add key="ConnStr" value="Data Source=localhost;database=company;UID=sa;Password=;Persist Security Info=True;" />
</appSettings>

資料列表顯示篇，

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;

//引用命名空間:SQL託管,設定檔
using System.Data.SqlClient;
using System.Configuration;

public partial class _Default : System.Web.UI.Page
{
protected SqlConnection myconn = new SqlConnection(ConfigurationSettings.AppSettings["ConnectionString"]);
//讀取web.config設定檔中的資料庫連接字串,並串連到指定的資料庫

protected void Page_Load(object sender, EventArgs e)
{
if(!IsPostBack)//判斷頁面是否第一次運行
{

string strsql="select * from Product";//定義一個資料庫的查詢字串
DataSet ds = new DataSet();
myconn.Open();//開啟資料庫連接
SqlDataAdapter command = new SqlDataAdapter(strsql,myconn);//表示用於填充DataSet 和更新SQL Server 資料庫的一組資料命令和一個資料庫連接
command.Fill(ds, "Product");
productList.DataSource = ds.Tables[0].DefaultView;
productList.DataBind();
ds.Clear();
myconn.Close();//關閉資料庫連接
}
}

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('您真的要刪除這條記錄嗎？')){return false;}");
}
}

}

資料添加篇

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('對不起，該產品編號已經存在！')");
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:表示要對SQL Server資料庫執行的一個Transact-SQL語句或預存程序
cmd_add.ExecuteNonQuery();//對串連執行Transact-SQL語句並返回受影響的行數。對於 UPDATE、INSERT 和 DELETE 語句，傳回值為該命令所影響的行數。對於所有其他類型的語句，傳回值為 -1。如果發生復原，傳回值也為 -1。
myconn.Dispose();
myconn.Close();
}
[/CODE

[COLOR=Red]資料顯示篇[/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對象讀取並返回一個記錄集
shows.DataSource = rd_show;//指向資料來源
shows.DataBind();//綁定資料
rd_show.Close();//關閉SqlDataReader
}
}
}

資料修改篇

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('儲存成功！')</script>");
Response.Redirect("show.aspx?id=" + ProductId);
}

資料刪除篇

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");
}
}

例子下載