NBear实例讲解

Nbear的接口主要是调用ObjectConvertor类的3大类方法：ToObject,ToList,ToDataTable。

主要功能：不同类型的对象可以通过类型属性的映射,进行转换，包括类与接口。对于两种类型毫无继承关系,且两种类型的数据需要转换时，Nbear是很有用的。

另外Nbear是开源代码,在类型转换的过程中,主要使用 System.Reflection.Emit;反射来取值并赋值到新对象。使用IL编程一定程度上提高了程序的效率。

要研究IL的网友，可以认真研究一下其源码。

数据模型

 1   public interface IUser
 2     {
 3 
 4         string Name
 5         {
 6             get;
 7             set;
 8         }
 9 
10         int Age
11         {
12             get;
13             set;
14         }
15 
16     }
17 
18     public class User : IUser
19     {
20         //需要无参数构造函数
21         public User()
22         {
23         }
24         public User(string name, int age, bool isvisible)
25         {
26             this.Name=name;
27             this.Age=age;
28             this.IsVisible=isvisible;
29         }
30 
31         public string Name
32         {
33             get;
34             set;
35         }
36 
37         public int Age
38         {
39             get;
40             set;
41         }
42         public bool IsVisible
43         {
44             get;
45             set;
46         }
47 
48     }

  1    using NBear.Mapping;
  2     using NBearLiteDemo.Model;
  3     class Program
  4     {
  5         //ObjectConvertor类:: ToObject；ToList；ToDataTable
  6         static void Main(string[] args)
  7         {
  8          
  9            
 10             User user=new User("Jefftary", 24, true);
 11             User[] users=new User[] { user,new User("Jackbaby",19,true)};
 12           
 13             User outputObject1 = ObjectConvertor.ToObject<User>(user);            
 14             User outputObject2 = ObjectConvertor.ToObject<IUser, User>(user);   
 15           
 16             //User-Others
 17             DataRow outputObject3 = ObjectConvertor.ToObject<DataRow>(user);                   
 18             Hashtable outputObject4 = ObjectConvertor.ToObject<Hashtable>(user);                
 19             NameValueCollection outputObject5 = ObjectConvertor.ToObject<NameValueCollection>(user);                
 20             Dictionary<string, object> outputObject6 = ObjectConvertor.ToObject<Dictionary<string, object>>(user);               
 21               
 22             //Others->User
 23             User outputObject31 = ObjectConvertor.ToObject<User>(outputObject3);
 24             User outputObject41 = ObjectConvertor.ToObject<User>(outputObject4);
 25             User outputObject51 = ObjectConvertor.ToObject<User>(outputObject5);     
 26             User outputObject61 = ObjectConvertor.ToObject<User>(outputObject5);
 27 
 28             object[] list=new object[] { outputObject1, outputObject2, outputObject3, outputObject4, outputObject5, outputObject6 };
 29             object[] list2=new object[] { outputObject31, outputObject41, outputObject51, outputObject61 };
 30 
 31              //Array->List<User>
 32             List<User> userList = ObjectConvertor.ToList<IUser, User>(users);
 33 
 34              //Array->DataTable->List<User>->DataTable
 35             DataTable userTable = ObjectConvertor.ToDataTable(users, typeof(User));
 36             List<User> userList1 = ObjectConvertor.ToList<DataRow, User>(userTable);
 37             List<User> userList2 = ObjectConvertor.ToList<IDataReader, User>(userTable);
 38             DataTable  userTable2=ObjectConvertor.ToDataTable(userList, typeof(User));
 39              
 40 
 41             ShowList(list,"[Object]",true);
 42             ShowList(list2, "[Object-Parse]", true);
 43 
 44             ShowList(users, "[Array]");
 45 
 46             ShowList(userTable, "[ToDataTable(users, typeof(User))]");
 47             ShowList(userList, "[ToList<IUser, User>(users)]");
 48            
 49             ShowList(userList1, "[ToList<DataRow, User>(userTable)]");
 50             ShowList(userList2, "[ToList<IDataReader, User>(userTable)]");            
 51             ShowList(userTable2, "[ToDataTable(userList, typeof(User))]");
 52        
 53 
 54             var th=Type.GetTypeHandle(3);
 55             
 56             Console.WriteLine(th);
 57             Console.ReadKey();
 58         }
 59         
 60         static void Show(object obj,bool showType=true)
 61         {  
 62             string printFormat="{0}:\r\n\t\t{1}\t{2}\t{3}\r\n";
 63             if(!showType)
 64                 printFormat="\trow:\t{1}\t{2}\t{3}";
 65 
 66             Type type=obj.GetType(); 
 67             if (type.Equals(typeof(User)))
 68             {
 69                 var user=obj as User;
 70                 Console.WriteLine(string.Format(printFormat, type, user.Name, user.Age, user.IsVisible));
 71             }
 72             else
 73             {   
 74                 //反射获取索引器 this[Name]
 75                 var prop = type.GetProperty("Item", new Type[] { typeof(string) });
 76                 if (prop!=null)
 77                 {
 78                     //DataRow,Hashtable,Dictionary,NameValueCollection
 79                     var name= prop.GetGetMethod().Invoke(obj, new object[] { "Name" });
 80                     var age= prop.GetGetMethod().Invoke(obj, new object[] { "Age" });
 81                     var visible= prop.GetGetMethod().Invoke(obj, new object[] { "IsVisible" });
 82                     Console.WriteLine("this[Name]:");
 83                     Console.WriteLine(string.Format(printFormat, type, name, age, visible));
 84                 }
 85             }
 86             
 87             //else if (type.Equals(typeof(NameValueCollection)))
 88             //{
 89             //    var nv=obj as NameValueCollection;
 90 
 91             //    Console.WriteLine(string.Format(printFormat, type, nv["Name"], nv["Age"], nv["IsVisible"]));
 92             //}
 93             //else if (type.Equals(typeof(DataRow)))
 94             //{
 95             //    var dr=obj as DataRow;
 96             //    Console.WriteLine(string.Format(printFormat, type, dr["Name"].ToString(), dr["Age"].ToString(), dr["IsVisible"].ToString()));
 97 
 98             //}
 99             //else if (typeof(IDataReader).IsAssignableFrom(type))
100             //{
101             //    var rd=obj as IDataReader;
102             //    Console.WriteLine(string.Format(printFormat, type, rd["Name"].ToString(), rd["Age"].ToString(), rd["IsVisible"].ToString()));
103 
104             //}
105             //else if (type.Equals(typeof(Dictionary<string, object>)))
106             //{
107             //    var dc=obj as Dictionary<string, object>;
108             //    Console.WriteLine(string.Format(printFormat, type, dc["Name"].ToString(), dc["Age"].ToString(), dc["IsVisible"].ToString()));
109             //}
110             //else if (type.Equals(typeof(Hashtable)))
111             //{
112             //    var ht=obj as Hashtable;
113             //    Console.WriteLine(string.Format(printFormat, type, ht["Name"].ToString(), ht["Age"].ToString(), ht["IsVisible"].ToString()));
114 
115             //}
116         }
117 
118         static void ShowList(object obj,string title="",bool showType=false)
119         {
120             Console.WriteLine(string.Format("----------------------------{0}------------------------",title));
121             Type  type=obj.GetType();
122             if (type.Equals(typeof(DataTable)))
123             {
124                 var tb=obj as DataTable;
125                 //for (int i=0; i<tb.Rows.Count; i++)
126                 //    Show(tb.Rows[i],showType);
127                 IDataReader reader=tb.CreateDataReader();
128                 while (reader.Read())
129                 {
130                     Show(reader, showType);
131                 }            
132 
133 
134             }
135             else if(type.IsGenericType && typeof(IEnumerable<>).MakeGenericType(typeof(object)).IsAssignableFrom(type))
136             {
137                 var list=obj as IEnumerable<object>;
138                 foreach (var item in list)
139                 {
140                     Show(item, showType);
141                 }
142             }
143             else if (type.IsArray)
144             {
145                 var ary=obj as Array;
146                 foreach (var item in ary)
147                 {
148                     Show(item,showType);
149                 }
150             }
151         }
152     
153 
154     }