How to use C++ ENUM with the UUserDefinedEnum Class

Development Programming & Scripting
1

Hello,

i have questions about the given UUserDefinedEnum Class.

  1. How to use UUserDefinedEnum on the right way / should this class be used for ENUMs?
  2. How can i create an ENUM with the given structures from the UUserDefinedEnum Class with the name of eg. ETestTypes?
  3. What is the purpose for a .cpp file? (In my knowledge, a cpp file is not needed for ENUMs)

I hope someone knows about the “UUserDefinedEnum Class”

Thanks for your help -

ETestTypes.h:

#pragma once

#include "CoreMinimal.h"
#include "Engine/UserDefinedEnum.h"
#include "ETestTypes.generated.h"

/**
 *
 */
UCLASS()
class PROJECTA_API UETestTypes : public UUserDefinedEnum
{
	GENERATED_BODY()
	
};

ETestTypes.cpp:

// Fill out your copyright notice in the Description page of Project Settings.


#include "ETestTypes.h"
1 Like
2

super confused why you would like to inherit from UUserDefinedEnum,
if you just want to create a custom enum just do:

#pragma once

#include "CoreMinimal.h"
#include "UObject/ObjectMacros.h"
#include "YourEnum.generated.h"

UENUM(BlueprintType)
enum class EYourEnum : uint8
{
	Something,
    SomethingOther,
    SomethingElse
};
1 Like
3

thanks for your answer. in general you are right, but because epic itself describes this class that way (and the first point is very interesting)

  1. EnumType is always UEnum::ECppForm::Namespaced (to comfortable handle names collisions)
  2. always have the last ‘_MAX’ enumerator, that cannot be changed by user
  3. Full enumerator name has form: ‘="">::’ An Enumeration is a list of named values.
4

Sure but name collisions are only a problem for enums, not enum classes, enum classes are strongly typed.

the _MAx for enumerations you can add yourself

UENUM(BlueprintType)
 enum class EYourEnum : uint8
 {
     Something,
     SomethingOther,
     SomethingElse,
     YourEnum_Max UMETA(Hidden),
 };

the names are a little harder, but in most cases, you don’t need names, if you just want to use the enum as a state value.

I think the only purpose of UUserDefinedEnum is to be able to create enums in the editor, which if you are using C++ anyway is not really necessary for you. In general, if you are using C++ it’s a good practice to define all your types in C++, enum classes, structs. This allows you to use them in C++ and in blueprints.

4 Likes
5

ok, thanks for the detailed explanation :slight_smile: