linqHelper(隨便寫寫,參照別人的)

1. using System;
2. using System.Data;
3. using System.Configuration;
4. using System.Linq;
5. using System.Web;
6. using System.Xml.Linq;
7. using System.Collections.Generic;
8. using System.Linq.Expressions;
9. using System.Data.Linq;
10. using Database;
12. /// <summary>
13. ///linqHelper 的摘要說明
14. /// </summary>
15. namespace Business
16. {
17.     public abstract class linqHelper<TDatabase>
18. where TDatabase : DataContext, new()
19.     {
20.         /// <summary>
21.         /// 查詢全部數據
22.         /// </summary>
23.         /// <typeparam name="T"></typeparam>
24.         /// <returns></returns>
25.         public static List<T> ReturnAllRows<T>(string conString) where T : class
26.         {
27.             TDatabase database = new TDatabase();
29.             database.Connection.ConnectionString = conString;
30.             return database.GetTable<T>().ToList<T>();
31.         }
32.         /// <summary>
33.         /// 查看是否存在數據
34.         /// </summary>
35.         /// <typeparam name="T"></typeparam>
36.         /// <param name="predicate"></param>
37.         /// <returns></returns>
38.         public static bool EntityExists<T>(string conString,Expression<Func<T, bool>> predicate)
39.         where T : class
40.         {
42.             TDatabase database = new TDatabase();
44.             database.Connection.ConnectionString = conString;
45.             return database.GetTable<T>().Where<T>(predicate).Count() > 0;
46.         }
47.         /// <summary>
48.         /// 有條件的查詢數據List<typeparamref name="數據源:DataContext"/>  Filter<typeparamref name="表的類名:orders"/> 
49.         /// 最後面的可以輸入LINQ查詢語句（p=>p.order_id="00001")或者(form o in orders where o.order_id>100 sleect o);
50.         /// </summary>
51.         /// <typeparam name="T"></typeparam>
52.         /// <param name="predicate"></param>
53.         /// <returns></returns>
54.         public static List<T> Filter<T>(string conString,Expression<Func<T, bool>> predicate)
55.         where T : class
56.         {
57.             TDatabase database = new TDatabase();
58.             
59.             database.Connection.ConnectionString = conString;
60.             return database.GetTable<T>().Where(predicate).ToList<T>();
61.         }
62.         /// <summary>
63.         /// 插入數據,好象只能一條,測試完弄個數據插入多條
64.         /// </summary>
65.         /// <typeparam name="T"></typeparam>
66.         /// <param name="entity"></param>
67.         public static void Insert<T>(string conString,T entity) where T : class
68.         {
69.             using (TDatabase database = new TDatabase())
70.             {
71.                 database.Connection.ConnectionString = conString;
72.                 database.GetTable<T>().InsertOnSubmit(entity);
73.                 database.SubmitChanges();
74.             }
75.         }
76.         /// <summary>
77.         /// 刪除指定數據,支持多條刪除  Expression<Func<T, bool>> predicate就是查詢語句，只能用：p=>p.user_id=="123"的語句！
78.         /// </summary>
79.         /// <typeparam name="T"></typeparam>
80.         /// <param name="predicate"></param>
81.         ///返回值：0 成功    -1 失敗
82.         public static int Delete<T>(string conString,Expression<Func<T, bool>> predicate)
83.         where T : class
84.         {
85.             if (EntityExists<T>(conString, predicate))
86.             {
87.                 using (TDatabase database = new TDatabase())
88.                 {
89.                     database.Connection.ConnectionString = conString;
90.                     T t = (T)database.GetTable<T>().Where<T>(predicate).Single();
91.                     database.GetTable<T>().DeleteOnSubmit(t);
92.                     database.SubmitChanges();
93.                 }
94.                 return 0;
95.             }
96.             return -1;
97.         }
98.         /// <summary>
99.         /// 返回分頁面數據
100.         /// </summary>
101.         /// <typeparam name="T"></typeparam>
102.         /// <param name="pageSize">一次取多少條數據</param>
103.         /// <param name="currerCount">當前提交的頁數字</param>
104.         /// <returns></returns>
105.         public static List<T> getpPgeRow<T>(string conString,int pageSize, int currerCount) where T : class
106.         {
107.             TDatabase database = new TDatabase();
109.             database.Connection.ConnectionString = conString;
110.             return database.GetTable<T>().Skip<T>((currerCount - 1) * pageSize).Take<T>(pageSize).ToList<T>();
111.         }
112.         /// <summary>
113.         /// 返回多少條數據
114.         /// </summary>
115.         /// <typeparam name="T"></typeparam>
116.         /// <param name="predicate"></param>
117.         /// <returns></returns>
118.         public static int getPageCount<T>(string conString,Expression<Func<T, bool>> predicate) where T : class
119.         {
120.             TDatabase database = new TDatabase();
122.             database.Connection.ConnectionString = conString;
123.             return database.GetTable<T>().Where<T>(predicate).Count();
124.         }
125.         /// <summary>
126.         /// 一次插入多條數據 
127.         /// </summary>
128.         /// <typeparam name="T"></typeparam>
129.         /// <param name="entity"></param>
130.         public static void insetRows<T>(string conString,List<T> entity) where T : class
131.         {
132.             using (TDatabase database = new TDatabase())
133.             {
134.                 database.Connection.ConnectionString = conString;
135.                 foreach(T t in entity.ToList())
136.                 {
137.                     database.GetTable<T>().InsertOnSubmit(t);
138.                     database.SubmitChanges();
139.                 }
140.                
141.             }
142.         }
143.     }
145. }