Dynamic hosting of unmanaged DLL calls

Recently, it is often seen that some people ask about hosting an unmanaged instance.DLLCall problems. Calling a dynamic library is actually very simple. ManyCodeAll are implementedDLL. I mainly talk about dynamic library loading.

It is easy to implement dynamic loading for hosted dynamic libraries.

/Files/dwwwing/dlldemo.rar

 Code  =  Assembly. LoadFile (filepath );  //  Here is the path of the dynamic library.  
  
Type TP =  Ass. GetType (dlltype );  //  Dlltype is the namespace + class name (namespace. Class) of the dynamic library file you need to call)  
  
Methodinfo Method  =  TP. getmethod (function );  //  Function to be executed  
  
  Object  Ob  =  Activator. createinstance (TP ); //  Create object  
  
Method. Invoke (OB,  Null  );  //  Execute the function. The last parameter is required for executing the function. If no parameter exists, it is null.  
  
 

For calls to unmanaged DLL. It is a little more complicated than hosting dynamic libraries, but it is also very simple.

Use three API functions: loadlibrary, getprocaddress, and freelibrary.

Use loadlibrary to load the unmanaged DLL into the memory. Call getprocaddress to obtain the function pointer to be called. Convert an unmanaged function pointer to a delegate. Call freelibrary to release the loaded unmanaged memory ).

 

Code  System;

  Using  System. Collections. Generic;

  Using  System. text;

  Using  System. runtime. interopservices;



  Namespace  Dlltest

{

  Public   Class  Dllinvoke

{

[Dllimport (  " Kernel32.dll  "  )]

  Private   Static   Extern  Intptr loadlibrary (  String  Path );



[Dllimport (  "  Kernel32.dll  "  )]

  Private   Static   Extern Intptr getprocaddress (intptr Lib,  String  Funname );



[Dllimport (  "  Kernel32.dll  "  )]

  Public   Static   Extern   Bool  Freelibrary (intptr Lib );



  Private  Intptr LiBr;



  Public Dllinvoke (  String  Path)

{

LiBr  =  Loadlibrary (PATH );

}

  Public  Delegate invoke (  String  Funname, type)

{

Intptr API  =  Getprocaddress (LiBr, funname );

  Return  (Delegate) Marshal. getdelegateforfunctionpointer (API, type );

}

 ~  Dllinvoke ()

{

Freelibrary (LiBr );  //  Release. Required  
  
}

}

}

 

After completing the above function declaration, we will first set a delegate.

 Code   Delegate   Bool  Dodllfunction ();  //  If the function to be executed has parameters, you can declare it.  
 
Dllinvoke  =   New  Dllinvoke (filepath );  //  Unmanaged DLL file path  
  
Dodllfunction show  =  (Dodllfunction) dllinvoke. Invoke (initfunction,  Typeof  (Dodllfunction ));  //  Initfunction is the name of the function to be executed.  
  
Show (); //  Execution method. You can determine whether to pass parameters according to the definition.  
  
 

 

 

 

How do you think it is very simple? Next, let's try it by yourself. If you have any questions, please contact me. I will give you a detailed answer.