/Visual Studio 2008/CSEmitAssembly/ReadMe.txt

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    CONSOLE APPLICATION : CSEmitAssembly Project Overview

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Use:



Reflection provides objects (of type Type) that encapsulate assemblies, 

modules and types. It allows us to



1. Access attributes in your program's metadata.

2. Examine and instantiate types in an assembly.

3. Dynamically load and use types.

4. Emit new types at runtime.



This example shows the use of 4. CSReflection demonstrates 2 and 3. 



The System.Reflection.Emit namespace allows emitting metadata and Microsoft

intermediate language (MSIL) at run time and optionally generate a portable

executable (PE) file on disk. 



CSEmitAssembly emits these two types and save them to an assembly on disk:



public class ClassA {

    // Fields

    private ClassB classBField;

    private String stringField;



    // Methods

    public void ClassAMethod()

    { this.classBField.ClassBMethod(null); }



    // Properties

    public ClassB ClassBProperty {

        get { return this.classBField; }

        set { this.classBField = value; }

    }

}



public class ClassB {

    // Fields

    private List<ClassA> classAList;

    private ClassA classAField;



    // Methods

    public void ClassBMethod(List<ClassA> list) {

        this.classAField.ClassAMethod();

    }



    // Properties

    public List<ClassA> ClassAList {

        get { return this.classAList; }

        set { this.classAList.AddRange(value); }

    }

}





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Implementation:



The ReflectionEmitLanguage Add-in of .NET Reflector 

(http://reflectoraddins.codeplex.com/)

translates the IL code of a given method into the C# code that would be 

needed to generate the same IL code using System.Reflection.Emit. We can 

first build a .NET assembly with the target types, then use the tool to 

generate the System.Reflection.Emit codes that emits the same types.



1. Define the assembly and the module.

(AppDomain.DefineDynamicAssembly, AssemblyBuilder.DefineDynamicModule)



2. Declare the types. (ModuleBuilder.DefineType)



3. Define the types' constructors, fields, properties, and methods.

(TypeBuilder.DefineConstructor, TypeBuilder.DefineField, 

TypeBuilder.DefineProperty, TypeBuilder.DefineMethod)



4. Create the types. (TypeBuilder.CreateType)



5. Save the assembly. (AssemblyBuilder.Save)





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References:



Emitting Dynamic Methods and Assemblies

http://msdn.microsoft.com/en-us/library/8ffc3x75.aspx



System.Reflection.Emit Namespace

http://msdn.microsoft.com/en-us/library/system.reflection.emit.aspx



Dynamic Assemblies using Reflection.Emit. Part II of II - Reflection.Emit

By Piyush S Bhatnagar

http://www.codeproject.com/KB/cs/DynamicCodeGeneration2.aspx



ReflectionEmitLanguage 

http://www.codeplex.com/reflectoraddins/Wiki/View.aspx?title=ReflectionEmitLanguage&referringTitle=Home





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