CODEWITHSUNDEEP
enumsc++-clinullable
azerty
azerty

Reputation: 777

How to cast a C# nullable Enum to int in c++/CLI

I would like to cast a C# nullable enum into an int.

For now, I have something like:

c#

public enum Dir
{
 Up = 0,
 Down = 1,
 Left = 2,
 Right = 3
}

c++/cli

function(System::Nullable<Dir> d){
   if(d != NULL){
       (int)d; error C2440: 'type cast' : cannot convert from 'System::Nullable<T>' to 'int' 
   }
}

So, how to cast a nullable enum ? There is no such nullable int c++/CLI or ?

Thanks

Upvotes: 1

Views: 1846

Answers (2)

David Yaw
David Yaw

Reputation: 27864

You need to use HasValue to test for null (C++/CLI won't let you compare against nullptr, for some reason), and you can use Value to retrieve the value, which can then be cast to integer. 

void function(System::Nullable<Dir> d){
   if(d.HasValue){
       int i = (int)d.Value;
   }
}

Upvotes: 3

SLaks
SLaks

Reputation: 887797

You should be able to access the value of the Nullable<T> with the .Value property, and cast that to int.

Disclaimer: I've never used C++/CLI

Upvotes: 0

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