How C++ DLL sends the error to C# exe

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I have an application whose UI is in C#, WPF and this UI is using c++ DLL for performing operations.
I am calling the c++ DLL methods from my UI in this way and it is working fine.
If C++ DLL will get some exception or error during execution then how can I pass the error with some integer value and string back to my c# exe, so that c# exe will update the UI as per the error and show the readable message to the user.

What I have tried:

I am thinking of using callbacks because an error can come at any time or from any method of DLL.
step1: register callback method of c# in c++
step2: Whenever error or exception came in DLL call this registered callback method of c# from c++ DLL.
step3: Run this callback method for infinite time in c# exe and whenever error comes from c++ DLL identify the error through error code and take corresponding actions.
I am not sure this approach is correct or not, if it's correct then how to implement it.

Posted 26-Jul-20 21:50pm

Member 14686752

Updated 28-Jul-20 5:46am

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2 solutions

Solution 2

Generally any error code generated by an API call can be queried with GetLastError() function and FormatMessage() can give textual representation of that error using FORMAT_MESSAGE_FROM_SYSTEM flag. Both of which you can call from the C# app

Posted 28-Jul-20 5:46am

steveb

Updated 28-Jul-20 5:48am

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KarstenK · Accepted Answer · 2020-07-26T21:58:00

Solution 1

Running an infinite loop is bad style. You should handle the error and than move by finding a way out.

Ensure that the C++ error are handled in C++ completly and you only inform C# about the occured issue.

Read my article about Callbacks between C++ and C#.

Posted 26-Jul-20 21:58pm

KarstenK

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Member 14686752 28-Jul-20 4:55am

Thanks for your response. Yeah, I used delegates for avoiding infinite loop. Your article gave me a good reference for resolving my issue.