Linq to sql 增删改查

最新推荐文章于 2023-05-03 18:45:57 发布

昕友软件

最新推荐文章于 2023-05-03 18:45:57 发布

阅读量119

点赞数

CC 4.0 BY-SA版权

本文链接：https://blog.youkuaiyun.com/starcrm/article/details/84969075

本文介绍了一个使用LINQ进行数据库操作的示例项目。该项目通过C#代码演示了如何从Northwind数据库中检索、插入、更新和删除数据。具体包括针对'Beverages'类别产品的查询、新增产品、修改价格及删除特定产品的操作。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

配置文件

代码：

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

namespace LINQPart1
{
    public partial class _Default : System.Web.UI.Page
    {

        protected void Page_Load(object sender, EventArgs e)
        {
            ShowProducts();
        }

        protected void Select_Click(object sender, EventArgs e)
        {
            ShowProducts();

}

        private void ShowProducts()
        {
            NorthwindDataContext db = new NorthwindDataContext();

            var products = from p in db.Products
                           where p.Category.CategoryName == "Beverages"
                           orderby p.ProductID descending
                           select new { p.ProductID, p.ProductName, p.Category.CategoryName, Price = p.UnitPrice };

            GridView1.DataSource = products;
            GridView1.DataBind();
        }

        protected void Insert_Click(object sender, EventArgs e)
        {
            NorthwindDataContext db = new NorthwindDataContext();

            Product p1 = new Product { CategoryID = 1, ProductName = "Scott's Apple Juice", UnitPrice = 4.23m };
            db.Products.InsertOnSubmit(p1);
            db.SubmitChanges();
            ShowProducts();
        }

        protected void Update_Click(object sender, EventArgs e)
        {
            NorthwindDataContext db = new NorthwindDataContext();

            Product product = db.Products.First(p => p.ProductName.StartsWith("Scott's"));
            product.UnitPrice += 2.25m;
            db.SubmitChanges();
            ShowProducts();
        }

        protected void Delete_Click(object sender, EventArgs e)
        {
            NorthwindDataContext db = new NorthwindDataContext();
            Product product = db.Products.First(p => p.ProductName.StartsWith("Scott's"));
            //foreach ()
            db.Products.DeleteOnSubmit(product);
            db.SubmitChanges();
            ShowProducts();

}
}
}