网上购物系统（Task004）——数据访问层DAL

一、添加类库DAL，在DAL中添加类Category.cs，并在类库中添加函数GetCategories(),代码如下：

using System;
using System.Data;
using System.Collections.Generic;
using System.Text;

using System.Data.SqlClient;
using WestGarden.Model;
using WestGarden.DBUtility;

namespace WestGarden.DAL
{
    public class Category
    {
        // Static constants
        private const string SQL_SELECT_CATEGORIES = "SELECT CategoryId, Name, Descn FROM Category";

        /// <summary>
        /// Method to get all categories
        /// </summary>
        public IList<CategoryInfo> GetCategories()
        {

IList<CategoryInfo> categories = new List<CategoryInfo>();

            //Execute a query to read the categories
            using (SqlDataReader rdr = SqlHelper.ExecuteReader(SqlHelper.ConnectionStringLocalTransaction, CommandType.Text, SQL_SELECT_CATEGORIES, null))
            {
                while (rdr.Read())
                {
                    CategoryInfo cat = new CategoryInfo(rdr.GetString(0), rdr.GetString(1), rdr.GetString(2));
                    categories.Add(cat);
                }
            }
            return categories;
        }

}
}

函数GetCategories()要在SQLHelper中读取连接字符串，因此，需要在SQLHelper.cs中添加代码：

public static readonly string ConnectionStringLocalTransaction = ConfigurationManager.ConnectionStrings["NetShopConnString"].ConnectionString;

注意添加引用System.Configuration。

二、使用用户控件

在Web中新建文件夹Controls并在其中添加用户控件NavigationControl.ascx，窗体页和代码页代码分别如下：

[html] <%@ Control Language="C#" AutoEventWireup="true" CodeFile="NavigationControl.ascx.cs" Inherits="WestGarden.Web.NavigationControl" %>
<%@ OutputCache Duration="100000" VaryByParam="*" %>

<asp:Repeater ID="repCategories" runat="server">
<HeaderTemplate>
<table cellspacing="0" border="0" style="border-collapse: collapse;">
</HeaderTemplate>
<ItemTemplate>
<tr>
<td class="<%= ControlStyle %>"><asp:HyperLink runat="server" ID="lnkCategory" NavigateUrl='<%# string.Format("~/Items.aspx?page=0&categoryId={0}", Eval("CategoryId")) %>' Text='<%# Eval("Name") %>' /><asp:HiddenField runat="server" ID="hidCategoryId" Value='<%# Eval("CategoryId") %>' /></td>
</tr>
</ItemTemplate>
<FooterTemplate>
</table>
</FooterTemplate>
</asp:Repeater>
<%@ Control Language="C#" AutoEventWireup="true" CodeFile="NavigationControl.ascx.cs" Inherits="WestGarden.Web.NavigationControl" %>
<%@ OutputCache Duration="100000" VaryByParam="*" %>

<asp:Repeater ID="repCategories" runat="server">
<HeaderTemplate>
<table cellspacing="0" border="0" style="border-collapse: collapse;">
</HeaderTemplate>
<ItemTemplate>
<tr>
<td class="<%= ControlStyle %>"><asp:HyperLink runat="server" ID="lnkCategory" NavigateUrl='<%# string.Format("~/Items.aspx?page=0&categoryId={0}", Eval("CategoryId")) %>' Text='<%# Eval("Name") %>' /><asp:HiddenField runat="server" ID="hidCategoryId" Value='<%# Eval("CategoryId") %>' /></td>
</tr>
</ItemTemplate>
<FooterTemplate>
</table>
</FooterTemplate>
</asp:Repeater>

[csharp] using System;
using System.Web.UI.WebControls;
using WestGarden.DAL;

namespace WestGarden.Web {
    public partial class NavigationControl : System.Web.UI.UserControl {

        private string controlStyle;

        protected string ControlStyle {
            get { return controlStyle; }
        }

        protected void GetControlStyle() {
            if (Request.ServerVariables["SCRIPT_NAME"].ToLower().IndexOf("default.aspx") > 0)
                controlStyle = "navigationLinks";
            else
                controlStyle = "mainNavigation";
        }


        protected void Page_Load(object sender, EventArgs e) {
            GetControlStyle();
            BindCategories();

            string categoryId = Request.QueryString["categoryId"];
            if (!string.IsNullOrEmpty(categoryId))
                SelectCategory(categoryId);
        }

        private void SelectCategory(string categoryId) {
     &nb

补充：Web开发 , ASP.Net ,