Calling unmanaged methods from C# application via CLR wrapper utility

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I need to use my C++ dll in C# application. I created a wrapper project in CLR and linked with C# app.
I am getting random crashes while accessing the memory created in c# application in my CLR wrapper methods and sometimes in my C++ dll project.
I am sure my dll project is a foolproof one.
I tested my code with messages to find the erroneous code.but i couldn't find out the reason.
C++ Class:

C++

class A
{
     public:
     A();
     ~A()
      int C++DllMethod(int*);
 };

CLR Wrapper Class:

C++

class A_Wrap
{
    A_Wrap();
    ~A_Wrap();
    int CLRDllMethod(int*);
};

C# Application:

int[] MyArray = { 10, 10, 10 };
     int* IntVal = null;
     fixed (int* ii = MyArray)
         IntVal = ii;
     A_Wrap Wrapper = new A_Wrap();
     Wrapper.CLRDllMethod(IntVal);

What I have tried:

"undefined value" is shown at the stack bar display for the pointer variable(int*) while crashing in CLR project.
I wonder the problem could be with the memory allocation in C# app and passing it to CLR wrapper project.
I tried pin_ptr concept in CLR project and it also didnt work for me.

Suggestions needed to avoid the crash.

Posted 15-Apr-16 1:52am

Member 10185036

Updated 15-Apr-16 2:50am

KarstenK

v3

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Comments

Philippe Mori 15-Apr-16 17:04pm

The wrapper project should have its own DLL and should be mixed-mode C++.

You should not do conversion on the C# side. Send CLR array to C++/CLI code and convert array to native C++ in that assembly. Otherwise, your application would be polluted by conversion code.

It is much more preferable to split code appropriatly.

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KarstenK · Answer 1 · 2016-04-15T02:50:00

Solution 1

you must allocate real memory for your array

C#

int[] MyArray = new int[3];

I dont think you need it, but it makes your intention clearer

C#

fixed (int* pointer = MyArray)
{
     A_Wrap Wrapper = new A_Wrap();
     Wrapper.CLRDllMethod(pointer);
    //all stuff with the array
}

Posted 15-Apr-16 2:50am

KarstenK