Discussion :

[sephirostoy]

Bonjour,

j'ai une Dll c++/cli qui fait le pont entre une lib C# et une appli C++.
Je souhaite pouvoir attrapper toutes les exceptions manag�s pour lancer des exceptions non manag� en transmettant le message d'erreur.

Je pense que le mieux c'est de le faire dans le code manag�. Le probl�me c'est que depuis l�, je n'arrive pas � cr�er un objet de type exception non manag� car le type "Exception" est manag� de ce point de vue l� de la Dll.

Donc voil�, comment lancer une Exception non manag� depuis du code manag� ?

[MABROUKI]

bonjour
le mieux � faire c'est que tu dis et ce que l'api .Net Framework permet .Le support .Net FrameWork est fourni pour des appels P/INVOKE et des Appel � des Interfaces Com .
1/PINVOKE (attribut Importdll)
-System.Exception.Marshal.GetLastWin32Error
-ennui: il faut se taper la sdk WIN32 pour les messages correspondant � chaque error code renvoye par la fonction.
code c# sharp

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using System;
using System.Runtime.InteropServices;
 
internal class Win32
{
    // Use DllImportAttribute to inport the Win32 MessageBox
    // function.  Set the SetLastError flag to true to allow
    // the function to set the Win32 error.
    [DllImportAttribute("user32.dll", SetLastError=true)]
    public static extern int MessageBox(IntPtr hwnd, String text, String caption, uint type);
 
}
 
class Program
{
 
    static void Run()
    {
        // Call the MessageBox with normal parameters.
 
        Console.WriteLine("Calling Win32 MessageBox without error...");
 
        Win32.MessageBox(new IntPtr(0), "Press OK...", "Press OK Dialog", 0);
 
        // Get the last error and display it.
        int error = Marshal.GetLastWin32Error();
 
        Console.WriteLine("The last Win32 Error was: " + error);
 
        // Call the MessageBox with an invalid window handle to
        // produce a Win32 error.
 
        Console.WriteLine("Calling Win32 MessageBox with error...");
 
        Win32.MessageBox(new IntPtr(123132), "Press OK...", "Press OK Dialog", 0);
 
        // Get the last error and display it.
 
        error = Marshal.GetLastWin32Error();
 
        Console.WriteLine("The last Win32 Error was: " + error);
    }
 
    static void Main(string[] args)
    {
        Run();
    }
}
// This code example displays the following to the console: 
//
// Calling Win32 MessageBox without error...
// The last Win32 Error was: 0
// Calling Win32 MessageBox with error...
// The last Win32 Error was: 1400

code c++/cli:

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using namespace System;
using namespace System::Runtime::InteropServices;
 
public value struct Point
{
public:
    property int X;
    property int Y;
};
extern bool CloseHandle(IntPtr h);
 
int main()
{
    // Demonstrate the use of public static fields of the Marshal
    // class.
    Console::WriteLine(
        "SystemDefaultCharSize={0},SystemMaxDBCSCharSize={1}",
        Marshal::SystemDefaultCharSize,
        Marshal::SystemMaxDBCSCharSize);
 
    // Demonstrate the use of the SizeOf method of the Marshal
    // class.
    Console::WriteLine("Number of bytes needed by a Point object: {0}",
        Marshal::SizeOf(Point::typeid));
    Point point;
    Console::WriteLine("Number of bytes needed by a Point object: {0}",
        Marshal::SizeOf(point));
 
    // Demonstrate how to call GlobalAlloc and 
    // GlobalFree using the Marshal class.
    IntPtr hglobal = Marshal::AllocHGlobal(100);
    Marshal::FreeHGlobal(hglobal);
 
    // Demonstrate how to use the Marshal class to get the Win32
    // error code when a Win32 method fails.
    bool isCloseHandleSuccess = CloseHandle(IntPtr(-1));
    if (!isCloseHandleSuccess)
    {
        Console::WriteLine(
            "CloseHandle call failed with an error code of: {0}",
            Marshal::GetLastWin32Error());
    }
};
 
// This is a platform invoke prototype. SetLastError is true,
// which allows the GetLastWin32Error method of the Marshal class
// to work correctly.    
[DllImport("Kernel32", ExactSpelling = true, SetLastError = true)]
extern bool CloseHandle(IntPtr h);
 
// This code produces the following output.
// 
// SystemDefaultCharSize=2, SystemMaxDBCSCharSize=1
// Number of bytes needed by a Point object: 8
// Number of bytes needed by a Point object: 8
// CloseHandle call failed with an error code of: 6

1/Appel � des interfaces COM
Lorsque du code manag� l�ve une exception, le runtime passe la valeur HRESULT au client COM(NB:passe automatiquement au system qui a genere la var exception HRESULT pour qu'il renseinge ses champs "). Lorsque du code non manag� retourne une erreur, la valeur HRESULT est convertie en une exception qui est ensuite lev�e par le runtime .Net FrameWork.
utilisation de "Exception.HResult" en code c# :

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// Example for the Exception.HResult property.
using System;
 
namespace NDP_UE_CS
{
    // Create the derived exception class.
    class SecondLevelException : Exception
    {
        const int SecondLevelHResult = unchecked( (int)0x81234567 );
 
        // Set HResult for this exception, and include it in 
        // the exception message.
        public SecondLevelException( string message, Exception inner ) :
            base( string.Format( "(HRESULT:0x{1:X8}) {0}", 
                message, SecondLevelHResult ), inner )
        {
            HResult = SecondLevelHResult;
        }
    }
 
    class HResultDemo 
    {
        public static void Main() 
        {
            Console.WriteLine( 
                "This example of Exception.HResult " +
                "generates the following output.\n" );
 
            // This function forces a division by 0 and throws 
            // a second exception.
            try
            {
                try
                {
                    int  zero = 0;
                    int  ecks = 1 / zero;
                }
                catch( Exception ex )
                {
                    throw new SecondLevelException( 
                        "Forced a division by 0 and threw " +
                        "a second exception.", ex );
                }
            }
            catch( Exception ex )
            {
                Console.WriteLine( ex.ToString( ) );
            }
        }
    }
}
 
/*
This example of Exception.HResult generates the following output.
 
NDP_UE_CS.SecondLevelException: (HRESULT:0x81234567) Forced a division by 0 and
 threw a second exception. ---> System.DivideByZeroException: Attempted to divi
de by zero.
   at NDP_UE_CS.HResultDemo.Main()
   --- End of inner exception stack trace ---
   at NDP_UE_CS.HResultDemo.Main()
*/

utilisation de "Exception.HResult" code c++/cli :

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// Example for the Exception::HResult property.
using namespace System;
 
namespace NDP_UE_CPP
{
 
   // Create the derived exception class.
   ref class SecondLevelException: public Exception
   {
   private:
      static int SecondLevelHResult = (int)0x81234567;
 
   public:
 
      // Set HResult for this exception, and include it in 
      // the exception message.
      SecondLevelException( String^ message, Exception^ inner )
         : Exception( String::Format( "(HRESULT:0x{1:X8}) {0}", message, SecondLevelHResult ), inner )
      {
         HResult = SecondLevelHResult;
      }
 
   };
 
 
   // This function forces a division by 0 and throws 
   // a second exception.
   void DivideBy0()
   {
      try
      {
         try
         {
            int zero = 0;
            int ecks = 1 / zero;
         }
         catch ( Exception^ ex ) 
         {
            throw gcnew SecondLevelException( "Forced a division by 0 and threw "
            "a second exception.",ex );
         }
 
      }
      catch ( Exception^ ex ) 
      {
         Console::WriteLine( ex->ToString() );
      }
 
   }
 
}
 
int main()
{
   Console::WriteLine( "This example of Exception::HResult "
   "generates the following output.\n" );
   NDP_UE_CPP::DivideBy0();
}
 
/*
This example of Exception::HResult generates the following output.
 
NDP_UE_CPP.SecondLevelException: (HRESULT:0x81234567) Forced a division by 0 an
d threw a second exception. ---> System.DivideByZeroException: Attempted to div
ide by zero.
   at NDP_UE_CPP.DivideBy0()
   --- End of inner exception stack trace ---
   at NDP_UE_CPP.DivideBy0()
*/

voici un exemple d'error handling pour un composant "hypothetique ATLCOMERRORSERVERLib" Com en c# que tu peux transposer en c+/cli :

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using System;
using ATLCOMERRORSERVERLib;
using System.Runtime.InteropServices;
 
namespace CSharpComErrorClient
{
    class ComErrorClient
    {
        // Helper function.
        static void ReportCOMError(COMException e)
        {
            Console.WriteLine("*********************");
            Console.WriteLine("Raw HRESULT: {0}", e.ErrorCode);
            Console.WriteLine("Message: {0}", e.Message);
            Console.WriteLine("Source of error: {0}", e.Source);
            Console.WriteLine("Method Name: {0}", e.TargetSite);
            Console.WriteLine("**********************\n");
        }
 
        [STAThread]
        static void Main(string[] args)
        {
            // Create the ATL coclass.
            TheBrokenObjectClass b = new TheBrokenObjectClass();
 
            // Trigger the errors.
            try
            {
                b.ReturnFailedHRESULT();
            }
            catch(COMException comEx)
            {
                ReportCOMError(comEx);
            }
            try
            {
                b.ReturnComErrorObject();
            }
            catch(COMException comEx)
            {
                ReportCOMError(comEx);
            }
        }
    }
}

nb: ennui des mappages des description d'error code n'existe pas en COM.
bon code...

[Respecteur]

la class exception c une class implementee dans la library , donc la class elle etre heritee, pour utiliser ses proprietees .