C#3.0 series: Anonymous Type in CLR (3.5)

We say that the anonymous type is a new feature of C # 3.0, not that anonymous type is a new feature of the. NET Framework 3.5. This is because the anonymous type is simply a newly introduced feature of the. NET programming language and the corresponding compiler. For the. NET Framework 3.5来, it does not see how this differs from the original, and there is no essential difference between the anonymous type and the general named type for the CLR.

Let's use a simple code like this:

1var p1 = new { Name = "IORI", Age = 27 };

And then we'll look at IL:

Code

1.method private hidebysig static void　Main(string[] args) cil managed
2{
3　.entrypoint
4　// Code size　　　 15 (0xf)
5　.maxstack　3
6　.locals init ([0] class '<>f__AnonymousType0`2'<string,int32> p1)
7　IL_0000:　nop
8　IL_0001:　ldstr　　　"IORI"
9　IL_0006:　ldc.i4.s　 27
10　IL_0008:　newobj　　 instance void class '<>f__AnonymousType0`2'<string,int32>::.ctor(!0,
11　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 　　　　　　　　　　　!1)
12　IL_000d:　stloc.0
13　IL_000e:　ret
14} // end of method Program::Main
15

We can see here again that compiler will create a type named <>F__ANONYMOUSTYPE0 ' 2<string,int32> for P1 this anonymous type. The arguments will be based on the specific structure of the data member, which is also declaring a type. This class inherits from object and overrides the implementation of ToString () and GetHashCode (). All anonymous types are automatically inherited from System.Object, and Equals (), GetHashCode (), and ToString () are overridden. The following figure:

The structure is as follows:

internal sealed class <>f__AnonymousType0<<Name>j__TPar, <Age>j__TPar>
{
　　// Fields
private readonly <Age>j__TPar <Age>i__Field;
　　　　private readonly <Name>j__TPar <Name>i__Field;

　　 // Methods
public <>f__AnonymousType0 (<Name>j__TPar Name, <Age>j__TPar Age);

　 　public override bool Equals(object value);
　　　　public override int GetHashCode();
　　　　public override string ToString();

　　// Properties
　　public <Age>j__TPar Age { get; }
　　public <Name>j__TPar Name { get; }
}