本例將講解 如何在 C++ 中建立一個多播委託，然後在執行時通知一組的 Actors（即廣播事件給監聽事件的物件們）

首先建立一個 繼承自 StaticMeshActor 的類，命名為 King

King.h

// the type name of new delegate signature being created
// the type of the signature's parameter
// the name of the signature's parameter
DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FOnKingDeathSignature, AKing*, DeadKing);	 // 委託簽名；OnKingDeath.Broadcast 和 Peasant::flee（函式指標） 的引數型別；Peasant::flee 引數名

UCLASS()
class TEST_API AKing : public AStaticMeshActor
{
	GENERATED_BODY()
	
public:	
	// Sets default values for this actor's properties
	AKing();

	// Called when the game starts or when spawned
	virtual void BeginPlay() override;
	
	// Called every frame
	virtual void Tick( float DeltaSeconds ) override;

	UFUNCTION(BlueprintCallable, Category = King)
	void Die();// 在關卡藍圖中呼叫，廣播委託

	UPROPERTY(BlueprintAssignable)	//  藍圖可以動態地為委託賦予事件
	FOnKingDeathSignature OnKingDeath;// 多播委託例項，在Broadcast之後呼叫該委託上的方法
	
};
 

King.cpp

// Sets default values
AKing::AKing()
{
 	// Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;
	auto MeshAsset = ConstructorHelpers::FObjectFinder<UStaticMesh>(TEXT("StaticMesh'/Engine/BasicShapes/Cone.Cone'"));
	if (MeshAsset.Object != nullptr)
	{
		GetStaticMeshComponent()->SetStaticMesh(MeshAsset.Object);
		GetStaticMeshComponent()->bGenerateOverlapEvents = true;
	}
	GetStaticMeshComponent()->SetMobility(EComponentMobility::Movable);
	
}

// Called when the game starts or when spawned
void AKing::BeginPlay()
{
	Super::BeginPlay();
	
}

// Called every frame
void AKing::Tick( float DeltaTime )
{
	Super::Tick( DeltaTime );

}

void AKing::Die()
{
	OnKingDeath.Broadcast(this);
}
 

Peasant.h

UCLASS()
class TEST_API APeasant : public AStaticMeshActor
{
	GENERATED_BODY()
public:
	APeasant();
	UFUNCTION(BlueprintCallable, category = Peasant)
	void Flee(AKing* DeadKing); // 自定義事件所繫結的函式
};

Peasant.cpp

APeasant::APeasant()
{
	auto MeshAsset = ConstructorHelpers::FObjectFinder<UStaticMesh>(TEXT("StaticMesh'/Engine/BasicShapes/Cube.Cube'"));
	if (MeshAsset.Object != nullptr)
	{
		GetStaticMeshComponent()->SetStaticMesh(MeshAsset.Object);
		GetStaticMeshComponent()->bGenerateOverlapEvents = true;
	}
	GetStaticMeshComponent()->SetMobility(EComponentMobility::Movable);

}
// 委託上繫結的函式引數為 King 的指標，所以 Broadcast 以該指標為引數
void APeasant::Flee(AKing* DeadKing)
{
	GEngine->AddOnScreenDebugMessage(-1, 2, FColor::Red, TEXT("Waily Waily!"));
	FVector FleeVector = GetActorLocation() - DeadKing->GetActorLocation();
	FleeVector.Normalize();
	FleeVector *= 500;
	SetActorLocation(GetActorLocation() + FleeVector);
}

編輯藍圖類：

然後，我們就可以將 King 類 和若干 BPPeasant 例項拖動到場景中

編輯關卡藍圖

設定一個延時，來廣播委託事件（Die 函式）

最後，我們就可以看到這樣一個效果——在5秒之後， King 周圍的 Peasant 都同時“遠離” King。