How to create custom event with array of structs as output node in Blueprint from C++

Development Programming & Scripting
1

I defined the following delegate in C++

DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FHostsReceivedDelegate, TArray<FHost>, Hosts);

And exposed it as a property

 UPROPERTY(BlueprintAssignable)
 FHostsReceivedDelegate HostsReceivedHandler;

In my BP I try to create a custom event to bind to it, but will get an error. With a different delegate it worked using FString and int32 as output types.

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Is this even possible and if so, what needs to be changed?

2

The declaration needs to be:

DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FReceivedHostsDelegate, TArray<FHost>, Hosts);
3

Nope. “Server.h(30): error : Missing ‘<’ in ‘tarray’” if i try: DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FUserServerDataDelegate, const TArray&, action);

4

EDIT
OK, i have it.

h

//Delegates
DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FUserServerDataDelegate, const TArray<FString>&, data);


UFUNCTION()
	void UserServerDataDelegate(const TArray<FString>& data);
UPROPERTY(BlueprintAssignable, Category = "0_UserData")
	FUserServerDataDelegate onUserServerDataDelegate;

cpp

UServer::UServer()
{
	//Delegate
	onUserServerDataDelegate.AddDynamic(this, &UServer::UserServerDataDelegate);
}

/*Delegate functions*/
void UServer::UserServerDataDelegate(const TArray<FString>& data) {}
5

You are right. I have edited the code. Even though it is the same as I gave in my question, I think in the end it was how I was binding the event in BP was wrong.

6

Nice, good work!

7

Sorry for updating the old topic but I met the same problem today. Does anybody know why it is required to pass TArray of structs by reference?

8

I’m also new to this so arrived here while looking for answers. Just in case anyone else stumbles across this page in future, allow me to try and be of assistance:

From what I understand, variables passed by reference are treated as output nodes and those that are not passed by reference are treated as input nodes. Simple as that.