Second C # dynamically generate code through emit

First, declareProgramSet Name,

 
//Specify a new Assembly nameVaRAssemblyname =NewAssemblyname ("Kitty");
 

Obtains the Assembly constructor from the current application domain,

 
//Create Assembly BuilderVaRAssemblybuilder =Appdomain. currentdomain. definedynamicassembly (assemblyname, assemblybuilderaccess. runandsave );
 

There are several types of dynamic assembly construction access restrictions:

• Assemblybuilderaccess. Run; indicates that the Assembly can be executed but cannot be saved.
• Assemblybuilderaccess. Save; indicates that the Assembly can be saved but cannot be executed.
• Assemblybuilderaccess. runandsave; indicates that the Assembly can be saved and executed.
• Assemblybuilderaccess. reflectiononly; indicates that an assembly can only be used to reflect the context and cannot be executed.
• Assemblybuilderaccess. runandcollect; indicates that the Assembly can be detached and the memory will be recycled.

Construct dynamic modules in a program set,

 
//Create module BuilderVaRModulebuilder = assemblybuilder. definedynamicmodule ("Kittymodule","Kitty.exe");
 

Module isCodeA set of programs can have multiple modules. In theory, each module can use differentProgramming LanguageImplementation, such as C #/VB.
Construct a Type constructor,

 
//Create type builder for a classVaRTypebuilder = modulebuilder. definetype ("Hellokittyclass", Typeattributes. Public );
 

Define a method through the Type constructor, obtain the method constructor, obtain the Il generator of the method constructor, and define the method function by writing the Il code.

       //  Create method Builder        VaR Methodbuilder = Typebuilder. definemethod (  " Sayhellomethod  "  , Methodattributes. Public | Methodattributes. Static,  Null  ,  Null  );  //  Then get the method il Generator        VaR IL = Methodbuilder. getilgenerator ();  //  Then create the method Function Il. emit (Opcodes. ldstr, "  Hello, kitty!  "  ); Il. emit (Opcodes. Call,  Typeof (Console). getmethod ( "  Writeline  " , New Type [] { Typeof ( String  )}); Il. emit (Opcodes. Call,  Typeof (Console). getmethod ("  Readline  "  ); Il. emit (Opcodes. Pop );  //  We just read something here, throw it. Il. emit (Opcodes. Ret );

Creation type,

 
//Then create the whole class typeVaRHellokittyclasstype = typebuilder. createtype ();
 

If the current Assembly is runnable, set a program entry,

//Set entry point for this AssemblyAssemblybuilder. setentrypoint (hellokittyclasstype. getmethod ("Sayhellomethod"));
 

Save the dynamically generated assembly as a disk file,

 
//Save assemblyAssemblybuilder. Save ("Kitty.exe");
 

Decompile kitty.exe into code through the decompilation tool,

 1   Using  System;  2   3  Public   Class  Hellokittyclass  4   {  5       Public   Static   Void  Sayhellomethod ()  6   {  7 Console. writeline ( "  Hello, kitty!  " );  8   Console. Readline ();  9   }  10 }

Running result,

Complete code

 1   Using  System;  2   Using  System. reflection;  3   Using  System. reflection. emit;  4  5   Namespace  Emitintroduction  6   {  7     Class  Program  8   {  9       Static   Void Main ( String  [] ARGs)  10   { 11         //  Specify a new Assembly name  12         VaR Assemblyname = New Assemblyname ( "  Kitty  "  );  13   14         //  Create Assembly Builder  15         VaR Assemblybuilder =Appdomain. currentdomain  16   . Definedynamicassembly (assemblyname, assemblybuilderaccess. runandsave );  17   18         //  Create module Builder  19         VaR Modulebuilder = assemblybuilder. definedynamicmodule ( "  Kittymodule  " , "  Kitty.exe "  );  20   21         //  Create type builder for a class  22         VaR Typebuilder = modulebuilder. definetype ( "  Hellokittyclass  "  , Typeattributes. Public );  23   24         //  Create method Builder 25         VaR Methodbuilder = Typebuilder. definemethod (  26           "  Sayhellomethod  "  ,  27 Methodattributes. Public | Methodattributes. Static,  28           Null  ,  29           Null  ); 30   31         //  Then get the method il Generator  32         VaR IL = Methodbuilder. getilgenerator ();  33   34         //  Then create the method Function  35 Il. emit (Opcodes. ldstr, "  Hello, kitty!  " );  36 Il. emit (Opcodes. Call, Typeof (Console). getmethod ( "  Writeline  " , New Type [] { Typeof ( String  )}));  37 Il. emit (Opcodes. Call, Typeof (Console). getmethod ( "  Readline "  ));  38 Il. emit (Opcodes. Pop ); //  We just read something here, throw it.  39   Il. emit (Opcodes. Ret );  40   41         //  Then create the whole class type  42         VaR Hellokittyclasstype = Typebuilder. createtype ();  43  44         //  Set entry point for this Assembly  45 Assemblybuilder. setentrypoint (hellokittyclasstype. getmethod ( "  Sayhellomethod  "  ));  46   47         //  Save assembly  48 Assemblybuilder. Save ( "  Kitty.exe "  );  49   50 Console. writeline ( "  Hi, Dennis, a kitty assembly has been generated for you.  "  );  51   Console. Readline ();  52   }  53   }  54 }

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