Linq 数据库通用的操作类

2008年12月7日 15:14

分类 : Asp.Net

摘要 : Linq Database class action generic

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;


namespace DAL
{
    public class Utility
    {
        public static void Insert<T>(T TEntity) where T : class
        {
            var table = TableFactory.CreateTable<T>();
            table.InsertOnSubmit(TEntity);
        }


        public static void Delete<T>(T TEntity) where T : class
        {
            var table = TableFactory.CreateTable<T>();
            table.DeleteOnSubmit(TEntity);
        }


        public static void Delete<T>(Func<T, bool> predicate) where T : class
        {
            var table = TableFactory.CreateTable<T>();
            var dResult = Where<T>(predicate);
            table.DeleteAllOnSubmit(dResult );
        }


        public static void Update<T>(T TEntity, Action<T> action)
        {
            action(TEntity);
            SubmitChanges();
        }


        public static void InsertAll<T>(IEnumerable <T> TEntities) where T : class
        {
            var table = TableFactory.CreateTable<T>();
            table.InsertAllOnSubmit( TEntities);
        }


        public static void DeleteAll<T>(IEnumerable<T> TEntities) where T : class
        {
            var table = TableFactory.CreateTable<T>();
            table.DeleteAllOnSubmit(TEntities);
        }


        public static IEnumerable<T> SelectAll<T>() where T : class
        {
            var table = TableFactory.CreateTable<T>();
            return table.Select(c => c).AsEnumerable();
        }


        public static IEnumerable<T> Where<T>(Func<T, bool> predicate) where T : class
        {
            var table = TableFactory.CreateTable<T>();
            return table.Where(predicate).AsEnumerable();
        }


        public static void SubmitChanges()
        {
            Database.NWDB.SubmitChanges();
        }
    }
}

同样的，我们也是写一些Test 方法来验证一下是否正确

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using DAL;
using DLinq;
using Toolkits;


namespace DALTest
{
    class Program
    {
        static void Main(string[] args)
        {
            //SelectAllTest();  
            InsertTest();
            WhereTest();
            UpdateTest();
            WhereTest();
            DeleteTest1();
            WhereTest();
            Console.WriteLine("All testings are success!");
            Console.Read();
        }


        private static void InsertTest()
        {
            Customer _customer=new Customer{ 
                CustomerID="Bruce",
                 ContactName="Lee",
                 CompanyName ="CodingSky",
                 City ="Shenzhen"};
            Utility.Insert(_customer);
            Utility.SubmitChanges();
        }


        private static void DeleteTest1()
        {
            Utility.Delete<Customer>(c => c.CustomerID == "Bruce");
            Utility.SubmitChanges();
        }


        private static void DeleteTest2()
        {
            var _result= Utility.Where<Customer>(c => c.CustomerID == "Bruce");
            if (_result.Count() > 0)
            {
                Utility.Delete(_result.First());
                Utility.SubmitChanges();
            }
        }


        private static void UpdateTest()
        {
            var _result= Utility.Where<Customer>(c => c.CustomerID == "Bruce");
            if (_result.Count() > 0)
            {
                var _customer = _result.First();
                if (_customer != null)
                {
                    Utility.Update(_customer, c =>
                    {
                        c.ContactName = "Jack";
                        c.CompanyName = "Microsoft";
                        c.City = "Beijing";
                    });
                    Utility.SubmitChanges();
                }
            }
        }


        private static void SelectAllTest()
        {
            var _result = Utility.SelectAll<Customer>();
            var _list = _result.ToList();
            if (_list.Count == 0)
            {
                Console.WriteLine("No result!");
                return;
            }
            _list.ForEach(c => Console.WriteLine(StringExtension.ToString(c)));
        }


        private static void WhereTest()
        {
            var _result= Utility.Where<Customer>(c => c.CustomerID == "Bruce");
            var _list = _result.ToList();
            if (_list.Count == 0)
            {
                Console.WriteLine("No result!");
                return;
            }
            Console.WriteLine("Query result is:");
            _list.ForEach(c => Console.WriteLine(StringExtension.ToString(c)));
        }
        
    }
}

其他代码（例如TableFactory，StringExtension）请参考上一篇：http://blog.csdn.net/fengart/archive/2008/08/19/2798534.aspx

以上的Test是先在Customers表中Insert一个叫Bruce的家伙，接着把他的ContactName修改为Jack ，最后Delete他。

（其中Customers表的数据太多，所以我把SelectAllTest方法注释掉了）

最后打印的结果应该是这样：

Query result is:
Class Name: Customer
        CustomerID: Bruce (String),
        CompanyName: CodingSky (String),
        ContactName: Lee (String),
        ContactTitle: (String),
        Address: (String),
        City: Shenzhen (String),
        Region: (String),
        PostalCode: (String),
        Country: (String),
        Phone: (String),
        Fax: (String),
        Orders: System.Data.Linq.EntitySet`1[DLinq.Order] (EntitySet`1)

Query result is:
Class Name: Customer
        CustomerID: Bruce (String),
        CompanyName: Microsoft (String),
        ContactName: Jack (String),
        ContactTitle: (String),
        Address: (String),
        City: Beijing (String),
        Region: (String),
        PostalCode: (String),
        Country: (String),
        Phone: (String),
        Fax: (String),
        Orders: System.Data.Linq.EntitySet`1[DLinq.Order] (EntitySet`1)

No result!
All testings are success!

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