Error: "No overload for method "foo" takes '4' arguments"

Error: "No overload for method "foo" takes '4' arguments"

• Tryst

  I had thought that [Runtime::InteropServices::In, Runtime::InteropServices::Out]^ implied ref.  Please correct me if I'm wrong as I don't know that there is a "ref" keyword in C++.  The error is complaining that no function exists with 4 arguments, it does not mention a type mismatch.  :(

  
  

• rajender reddy

  I thought using Runtime::InteropServices::In, Runtime::InteropServices::Out meant using "ref" in C#:
  myClass.myFunc(a, b, ref c, d);

  But, there is an error for that; "no overload that takes 4 parameters" seems strange.

  Are you missing a reference caret (^) on the Target argument of the myFunc declaration

  
  
  

• Jonathon Stevens

  Appologies for being so brief before, I actually wasn't near the code.

  Made an example solution today with the same problem.
  The Solution comtains two projects, a C# project (InteropExample) and a C++ project (myClass). 
  Inside the C++ project is one file (aside from stdafx), myClass.cpp.  
  Inside the C# project are two non-default files, Program.cs and Target.cs.
  The C++ project has a reference to the executible object of the C# project while the C# project has a reference to the C++ project, this was done to eliminate circular dependencies but allow the C++ project to access the C# defined classes.  In InteropExample a call is made to a static method of myClass (myCPPNamespace::myClass.myFunc) that requires 4 parameters.  When I attempt to compile I get an error "No Overload for method 'myFunc' takes '4' arguments," the metadata produced from Program.cs with "Go To Definition" shows the expected function.

  Here are some of the files:
  Program.cs:

  using System;
  using System.Collections.Generic;
  using System.Windows.Forms;

  using myCPPNamespace;
  using SESTool;

  namespace IntropExample
  {
      static class Program
      {
          /// <summary>
          /// The main entry point for the application.
          /// </summary>
          [STAThread]
          static void Main()
          {
              Target a;
              byte [] b = new byte[10];
              byte [] c = new byte[10];
              bool d;

              myClass.myFunc(a, b, c, d);

          }
      }
  }

  myClass.cpp:

  // SPTI.cpp : Defines the entry point for the DLL application.
  //

  #include "stdafx.h"

  #pragma managed

  using namespace System;

  namespace myCPPNamespace
  {
   public ref class myClass
   {

   public:
    myClass(void){};
    
    static bool myClass::myFunc([Runtime::InteropServices::In]SESTool::Target a,
            [Runtime::InteropServices::In]array<Byte>^ b,
            [Runtime::InteropServices::In, Runtime::InteropServices::Out]array<Byte>^ c,
            [Runtime::InteropServices::In]bool d)
    { return true; };
   };
  }

  Target.cs:

  using System;
  using System.Collections.Generic;
  using System.Text;

  
  namespace SESTool
  {
      public class Target
      {

  
          //---------------------------------------------------------------------
          public Target()
          {

          }

  
      }
  }

  myClass[from metadata]:

  using SESTool;
  using System;

  namespace myCPPNamespace
  {
      public class myClass
      {
          public myClass();

          public static bool myFunc(Target a, byte[] b, byte[] c, bool d);
      }
  }
  

  
  

• dxx

  It's probably because there is no overload that takes those types of 4 arguments.

  See Short but complete programs on how to post code samples that provide enough information for someone to accurately help you.

  
  
  

• ehsan707

  You've not defined byte[] c as ref. ....or should it be out
  
  

• chaza

  Peter Ritchie wrote:

  Can you post the line that causes the "no overload for..." error.

  For the example above the line is:

  return myClass.foo(a, b, ref c, d);

  In the test code the line looks more like this:

  return SPTIWrapper.SendAspi32Command(target, cdb, ref buffer, write);

  where Target target, byte [] cdb, ref byte[] buffer, bool write

  Devan

  
  

• su45937

  Thanks Peter, that was it.
  

• isaacb

  Can you post the line that causes the "no overload for..." error.
  
  
  

• Juergen Lorenz

  Peter Ritchie wrote:

  DevanL wrote: Thanks Peter, that was it. The "ref" or the caret

  The caret on 'target'

  
  

• AlexBB

  DevanL wrote:

  Thanks Peter, that was it.

  The "ref" or the caret
  
  
• Error: "No overload for method "foo" takes '4' arguments"