3C数码商城——三层架构DAL层

DAL层前面的创建与Model层一样，不一样的是多出来了SqlHelper。SqlHelper我们前面有写。

ProductCategoryService.cs

[code]using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Model
{
/// <summary>
/// 产品类别表
/// </summary>
public class ProductCategory
{
/// <summary>
/// 主键Id
/// </summary>
public int Id { get; set; }
/// <summary>
/// 类别名称
/// </summary>
public string Name { get; set; }
}
}

 ProductService.cs

[code]using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using Model;

namespace DAL
{
public class ProductService
{
/// <summary>
/// 查询
/// </summary>
/// <param name="name"></param>
/// <param name="category"></param>
/// <returns></returns>
public static DataTable Select(string name = "", int category = 0)
{
var sql = "select Product.*,ProductCategory.Name from ProductCategory,Product where ProductCategory.Id=Product.CategoryId ";
if (category > 0)
{
sql += "and Product.CategoryId= " + category;
}

if (!string.IsNullOrEmpty(name))
{
sql+=string.Format( "and ProductName like'%{0}%'",name);
}
return SqlHelp.Query(sql);
}
/// <summary>
/// 根据id查找
/// </summary>
/// <param name="id"></param>
/// <returns></returns>
public static Product Selectid(int id)
{
string sql = string.Format(" select * from Product where Id = {0} ", id);
var table = SqlHelp.Query(sql);
if (table.Rows.Count < 1)
return null;
var row = table.Rows[0];
return new Product()
{
Id =Convert.ToInt32(row["Id"]),
AddTime = Convert.ToDateTime(row["AddTime"]),
CategoryId = Convert.ToInt32(row["CategoryId"]),
Introduction = Convert.ToString(row["Introduction"]),
IsOnSale = Convert.ToInt32(row["IsOnSale"]),
MarketPrice = Convert.ToDouble(row["MarketPrice"]),
ProductName = Convert.ToString(row["ProductName"]),
SellingPrice = Convert.ToDouble(row["SellingPrice"]),
};
}
/// <summary>
/// 删除
/// </summary>
/// <param name="id"></param>
/// <returns></returns>
public static int Delete(int id)
{
var sql = "delete from product where Id=" + id;
return SqlHelp.NoneQuery(sql);
}
/// <summary>
/// 修改
/// </summary>
/// <param name="product"></param>
/// <returns></returns>
public static int Update(Product product)
{
var sql = string.Format("update Product set ProductName='{0}',MarketPrice='{1}',SellingPrice='{2}',CategoryId='{3}',Introduction='{4}',IsOnSale='{5}' where Id='{6}'",
product.ProductName,product.MarketPrice,product.SellingPrice,product.CategoryId,product.Introduction,product.IsOnSale,product.Id);
return SqlHelp.NoneQuery(sql);
}

}
}

 DAL是数据库中的重点，增删改查都需要写在里面，如果测试sql语句不确定可在数据库中先试一下。