4.net基础之委托事件

1  public class Company
2     {
3         public int Id { get; set; }
4         public string Name { get; set; }
5         public DateTime CreateTime { get; set; }
6         public int CreatorId { get; set; }
7         public int? LastModifierId { get; set; }
8         public DateTime? LastModifyTime { get; set; }
9     }

 1     public class DBHelper<T> where T:class,new()
 2     {
 3         private static string connectionStr = ConfigurationManager.ConnectionStrings["connectionStr"].ConnectionString;
 4 
 5         private W ExecuteSql<W>(string sql,Func<IDbCommand,W> func) {
 6             using (SqlConnection conn = new SqlConnection(connectionStr))
 7             {
 8                 IDbCommand command = conn.CreateCommand();
 9                 conn.Open();
10                 return func(command); 
11             }
12         }
13         public bool Add(T t)
14         {
15             Type type = typeof(T);
16             var c = string.Join(",", type.GetProperties().Where(p => p.Name != "Id").Select(p => string.Format("[{0}]", p.Name)));
17             var v = string.Join(",", type.GetProperties().Where(p => p.Name != "Id").Select(p => string.Format("@{0}", p.Name)));
18             var list = new List<SqlParameter>();
19             foreach (var item in type.GetProperties().Where(p => p.Name != "Id"))
20             {
21                 list.Add(new SqlParameter("@" + item.Name, item.GetValue(t)));
22             }
23             string sql = string.Format("insert into {0} ({1}) values ({2});", type.Name, c, v);
24 
25             return ExecuteSql<bool>(sql, cmd =>
26             {
27                 foreach (var item in list)
28                 {
29                     cmd.Parameters.Add(item);
30                 }
31                 cmd.CommandText = sql;
32                 cmd.CommandType = CommandType.Text;
33                 bool isAdded = cmd.ExecuteNonQuery() > 0;
34                 cmd.Connection.Close();
35                 return isAdded;
36             });
37         }
38 
39         public bool Delete(int id)
40         {
41             string sql = "DELETE FROM [dbo].[Company] where Id=@Id";
42             return ExecuteSql<bool>(sql, cmd =>
43             {
44                 cmd.Parameters.Add(new SqlParameter("@Id", id));
45                 cmd.CommandText = sql;
46                 cmd.CommandType = CommandType.Text;
47                 bool isDeleted = cmd.ExecuteNonQuery()>0;
48                 cmd.Connection.Close();
49                 return isDeleted;
50             }); 
51         }
52 
53         public bool Update(T t) {
54             Type type = typeof(T);
55             var c = string.Join(",", type.GetProperties().Where(p => p.Name != "Id").Select(p => string.Format("[{0}]=@{1}", p.Name,p.Name)));
56             var list = new List<SqlParameter>();
57              
58             foreach (var item in type.GetProperties())
59             {
60                 list.Add(new SqlParameter("@" + item.Name,item.GetValue(t)));
61             }
62             string sql = string.Format("UPDATE [dbo].[Company] SET {0} where Id = @Id",c);
63             return ExecuteSql<bool>(sql, cmd =>
64             {
65                 foreach (var item in list)
66                 {
67                     cmd.Parameters.Add(item);
68                 } 
69                 cmd.CommandText = sql;
70                 cmd.CommandType = CommandType.Text;
71                 bool isUpdated = cmd.ExecuteNonQuery() > 0;
72                 cmd.Connection.Close();
73                 return isUpdated; 
74             }); 
75         }
76         public IList<T> Query() {
77             return null;
78         }
79 
80         public IList<T> Query(string where) {
81             return null;
82         }
83     }