Linq入门实例

 1.数据定义

using System;
using System.Collections.Generic;
using System.Web;
using System.Linq;
using System.Data.Linq;
using System.Data.Linq.Mapping;

namespace QuickStart
{
    [Table]
    public class Cat
    {
       
        private int catId;

        private string name;
        private char sex;
        private float weight;

        public Cat()
        {
        }
        [Column(IsDbGenerated=true,AutoSync=AutoSync.OnInsert,IsPrimaryKey = true)]       

        public virtual int CatId
        {
            get { return catId; }
            set { catId = value; }
        }
        [Column] 
        public virtual string Name
        {
            get { return name; }
            set { name = value; }
        }
        [Column] 
        public virtual char Sex
        {
            get { return sex; }
            set { sex = value; }
        }
        [Column] 
        public virtual float Weight
        {
            get { return weight; }
            set { weight = value; }
        }

    }
}

 2.数据访问

string conn = "Server=(local);initial catalog=Test;uid=sa;pwd=abc123_";
protected void Page_Load(object sender, EventArgs e)
{
　　DataContext db = new DataContext(conn);
　　Table<Cat> catTable = db.GetTable<Cat>();
　  Cat c1 = catTable.Where(t => t.CatId == 3).FirstOrDefault();
　　Response.Write(c1.Name);       

}

删除，修改，查询

 public DataSet GetAll()
{
　　DataSet ds = new DataSet();
　　DataContext db = new DataContext(conn);
　　Table<Cat> catTable = db.GetTable<Cat>();
　   string sql = "select * from cat";
　　SqlDataAdapter adapter = new SqlDataAdapter(sql,conn);
　　adapter.Fill(ds);
　　return ds;
}

public int DeleteCat(int CatId)
{
　　DataContext db = new DataContext(conn);
　　Table<Cat> catTable = db.GetTable<Cat>();
　　Cat c1 = catTable.Where(t => t.CatId == CatId).FirstOrDefault();
　　catTable.DeleteOnSubmit(c1);
　　db.SubmitChanges();
　　return 1;
}

public int UpdateCat(int CatId,string Name,char Sex,float Weight,int CustomerId)
{
　　DataContext db = new DataContext(conn);
　　Table<Cat> catTable = db.GetTable<Cat>();
　　Cat c1 = catTable.Where(t => t.CatId == CatId).FirstOrDefault();
　　c1.Name = Name;
　　c1.Sex = Sex;
　　c1.Weight = Weight;
　　db.SubmitChanges();
　　return 1;

}