linqHelper代码,CSharp代码库,德仔网

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【CSharp】 linqHelper
作者:Ingram / 发布于2016/1/8/ 1021

	using System;
	using System.Data;
	using System.Configuration;
	using System.Linq;
	using System.Web;
	using System.Xml.Linq;
	using System.Collections.Generic;
	using System.Linq.Expressions;
	using System.Data.Linq;
	using Database;
	/// <summary>
	///linqHelper 的摘要说明 a
	/// </summary>
	namespace Business
	{
	 public abstract class linqHelper<TDatabase>
	where TDatabase : DataContext, new()
	 {
	 /// <summary>
	 /// 查询全部数据
	 /// </summary>
	 /// <typeparam name="T"></typeparam>
	 /// <returns></returns>
	 public static List<T> ReturnAllRows<T>(string conString) where T : class
	 {
	 TDatabase database = new TDatabase();
	 database.Connection.ConnectionString = conString;
	 return database.GetTable<T>().ToList<T>();
	 }
	 /// <summary>
	 /// 查看是否存在数据
	 /// </summary>
	 /// <typeparam name="T"></typeparam>
	 /// <param name="predicate"></param>
	 /// <returns></returns>
	 public static bool EntityExists<T>(string conString,Expression<Func<T, bool>> predicate)
	 where T : class
	 {
	 TDatabase database = new TDatabase();
	 database.Connection.ConnectionString = conString;
	 return database.GetTable<T>().Where<T>(predicate).Count() > 0;
	 }
	 /// <summary>
	 /// 有条件的查询数据List<typeparamref name="数据源:DataContext"/> Filter<typeparamref name="表的类名:orders"/>
	 /// 最后面的可以输入LINQ查询语句（p=>p.order_id="00001")或者(form o in orders where o.order_id>100 sleect o);
	 /// </summary>
	 /// <typeparam name="T"></typeparam>
	 /// <param name="predicate"></param>
	 /// <returns></returns>
	 public static List<T> Filter<T>(string conString,Expression<Func<T, bool>> predicate)
	 where T : class
	 {
	 TDatabase database = new TDatabase();
	
	 database.Connection.ConnectionString = conString;
	 return database.GetTable<T>().Where(predicate).ToList<T>();
	 }
	 /// <summary>
	 /// 插入数据,好象只能一条,测试完弄个数据插入多条
	 /// </summary>
	 /// <typeparam name="T"></typeparam>
	 /// <param name="entity"></param>
	 public static void Insert<T>(string conString,T entity) where T : class
	 {
	 using (TDatabase database = new TDatabase())
	 {
	 database.Connection.ConnectionString = conString;
	 database.GetTable<T>().InsertOnSubmit(entity);
	 database.SubmitChanges();
	 }
	 }
	 /// <summary>
	 /// 删除指定数据,支持多条删除 Expression<Func<T, bool>> predicate就是查询语句，只能用：p=>p.user_id=="123"的语句！
	 /// </summary>
	 /// <typeparam name="T"></typeparam>
	 /// <param name="predicate"></param>
	 ///返回值：0 成功 -1 失败
	 public static int Delete<T>(string conString,Expression<Func<T, bool>> predicate)
	 where T : class
	 {
	 if (EntityExists<T>(conString, predicate))
	 {
	 using (TDatabase database = new TDatabase())
	 {
	 database.Connection.ConnectionString = conString;
	 T t = (T)database.GetTable<T>().Where<T>(predicate).Single();
	 database.GetTable<T>().DeleteOnSubmit(t);
	 database.SubmitChanges();
	 }
	 return 0;
	 }
	 return -1;
	 }
	 /// <summary>
	 /// 返回分页面数据
	 /// </summary>
	 /// <typeparam name="T"></typeparam>
	 /// <param name="pageSize">一次取多少条数据</param>
	 /// <param name="currerCount">当前提交的页数字</param>
	 /// <returns></returns>
	 public static List<T> getpPgeRow<T>(string conString,int pageSize, int currerCount) where T : class
	 {
	 TDatabase database = new TDatabase();
	 database.Connection.ConnectionString = conString;
	 return database.GetTable<T>().Skip<T>((currerCount - 1) * pageSize).Take<T>(pageSize).ToList<T>();
	 }
	 /// <summary>
	 /// 返回多少条数据
	 /// </summary>
	 /// <typeparam name="T"></typeparam>
	 /// <param name="predicate"></param>
	 /// <returns></returns>
	 public static int getPageCount<T>(string conString,Expression<Func<T, bool>> predicate) where T : class
	 {
	 TDatabase database = new TDatabase();
	 database.Connection.ConnectionString = conString;
	 return database.GetTable<T>().Where<T>(predicate).Count();
	 }
	 /// <summary>
	 /// 一次插入多条数据
	 /// </summary>
	 /// <typeparam name="T"></typeparam>
	 /// <param name="entity"></param>
	 public static void insetRows<T>(string conString,List<T> entity) where T : class
	 {
	 using (TDatabase database = new TDatabase())
	 {
	 database.Connection.ConnectionString = conString;
	 foreach(T t in entity.ToList())
	 {
	 database.GetTable<T>().InsertOnSubmit(t);
	 database.SubmitChanges();
	 }
	
	 }
	 }
	 }
	}
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