介绍

对于标记有BlueprintImplementableEvent或者BlueprintNativeEvent的C++和蓝图函数，能够被C#重写函数逻辑。

注意

UE5.5开始对C++类BlueprintNativeEvent函数做了改动，插件从UE5.5开始不再支持覆盖C++类BlueprintNativeEvent函数，参看Change the code generation of UHT for BP implementable events to check for any script implementations of the event.。

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流程

1. 通过Partial，新建一个函数所属类的Partial类，并且标记Override
2. 声明一个拥有相同函数签名的函数，并且同样需要标记Override
   • 普通函数：C++或蓝图函数名Test，C#函数名Test
   • RPC函数：C++或蓝图函数名Server_Test，C#函数名Server_Test_Implementation

示例：覆盖函数

C++

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "TestCSharpFunctionActor.generated.h"

UCLASS()
class UNREALCSHARPTEST_API ATestCSharpFunctionActor : public AActor
{
	GENERATED_BODY()

public:
	// Sets default values for this actor's properties
	ATestCSharpFunctionActor();

public:
	UFUNCTION(BlueprintCallable, BlueprintImplementableEvent)
	void SetInt32ValueFunction(int32 InInt32Value);

	UFUNCTION(BlueprintCallable, BlueprintImplementableEvent)
	int32 GetInt32ValueFunction() const;

	UFUNCTION(BlueprintCallable, BlueprintImplementableEvent)
	void OutInt32ValueFunction(int32& OutInt32Value) const;
};

C#

using Script.CoreUObject;

namespace Script.UnrealCSharpTest
{
    [Override]
    public partial class ATestCSharpFunctionActor
    {
        [Override]
        public void SetInt32ValueFunction(int InInt32Value)
        {
            Int32Value = InInt32Value;
        }

        [Override]
        public int GetInt32ValueFunction()
        {
            return Int32Value;
        }

        [Override]
        public void OutInt32ValueFunction(ref int OutInt32Value)
        {
            OutInt32Value = Int32Value;
        }
    }
}

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代码扫描

在生成C#工程的时候，会先通过Microsoft.CodeAnalysis.CSharp对项目代码进行一次代码扫描，分析出标记有Override的类和函数，并且生成到项目/Intermediate/CodeAnalysis中，避免覆盖函数后续再生成，导致重定义。

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