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TSubclassOf

TSubclassOf is a template class that provides UClass type safety.

/** type of damage */
UPROPERTY(EditDefaultsOnly, Category=Damage)
TSubclassOf<UDamageType> DamageType;

And

UClass* ClassA = UDamageType::StaticClass();

TSubclassOf<UDamageType> ClassB;

ClassB = ClassA; // Performs a runtime check

TSubclassOf<UDamageType_Lava> ClassC;

ClassB = ClassC; // Performs a compile time check