介绍

通过UE提供的反射，插件会根据配置生成指定模块和插件下的类，结构体，枚举，以及资源类型。

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基础概念

UE和C#两侧的反射类型存在一一对应关系，对于简单类型比较容易理解，针对如UObject，蓝图等此类复杂类型，需要先了解一下UE中Package的概念，推荐UE4的资源管理和[中文直播]第33期 | UE4资产管理基础1 | Epic 大钊。

C++

如AActor，会将/Script/Engine.Actor映射为Script.Engine.Actor，规则为去掉首位/，并将/替换为.

Blueprint

如BP_TestReflectionPropertyActor_C，会将/Game/UnitTest/Reflection/BP_TestReflectionPropertyActor.BP_TestReflectionPropertyActor_C映射为Script.Game.UnitTest.Reflection.BP_TestReflectionPropertyActor_C，规则为加上Script/，去掉BP_TestReflectionPropertyActor.，并将/替换为.

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数据类型

针对不同的数据类型，有不同的处理方式，分为以下几个大类。

基本类型

C++	C#
bool	bool
int8	sbyte
int16	short
int32	int
int64	long
uint8	byte
uint16	ushort
uint32	uint
uint64	ulong
float	float
double	double

字符串

C++	C#
FName	Script.CoreUObject.FName
FText	Script.CoreUObject.FText
FString	Script.CoreUObject.FString

枚举

对于枚举和TEnumAsByte都会被对应到映射关系下的枚举。

示例：枚举

C++

UENUM(BlueprintType)
enum ETestEnum
{
	TestEnumZero,
	TestEnumOne,
	TestEnumTwo
};

C#

using Script.CoreUObject;

namespace Script.UnrealCSharpTest
{
	[PathName("/Script/UnrealCSharpTest.ETestEnum")]
	public enum ETestEnum : byte
	{
		TestEnumZero = 0,
		TestEnumOne = 1,
		TestEnumTwo = 2,
	}
}

结构体

会生成反射变量，StaticStruct，构造函数和析构函数等。

示例：结构体

C++

USTRUCT(BlueprintType)
struct FTestStruct
{
	GENERATED_BODY()

	UPROPERTY(BlueprintReadWrite)
	int32 Value;
};

C#

using Script.Library;
using Script.CoreUObject;

namespace Script.UnrealCSharpTest
{
	[PathName("/Script/UnrealCSharpTest.TestStruct")]
	public partial class FTestStruct : IStaticStruct, IGarbageCollectionHandle
	{
		public static UScriptStruct StaticStruct()
		{
			return UStructImplementation.UStruct_StaticStructImplementation("/Script/UnrealCSharpTest.TestStruct");
		}

		public FTestStruct() => UStructImplementation.UStruct_RegisterImplementation(this, Utils.GetPathName(GetType()));

		~FTestStruct() => UStructImplementation.UStruct_UnRegisterImplementation(GarbageCollectionHandle);

		public static bool operator ==(FTestStruct A, FTestStruct B) => UStructImplementation.UStruct_IdenticalImplementation(StaticStruct().GarbageCollectionHandle, A?.GarbageCollectionHandle??nint.Zero, B?.GarbageCollectionHandle??nint.Zero);

		public static bool operator !=(FTestStruct A, FTestStruct B) => !UStructImplementation.UStruct_IdenticalImplementation(StaticStruct().GarbageCollectionHandle, A?.GarbageCollectionHandle??nint.Zero, B?.GarbageCollectionHandle??nint.Zero);

		public override bool Equals(object Other) => this == Other as FTestStruct;

		public override int GetHashCode() => (int)GarbageCollectionHandle;

		public int Value
		{
			get => FPropertyImplementation.FProperty_GetStructInt32PropertyImplementation(GarbageCollectionHandle, __Value);

			set => FPropertyImplementation.FProperty_SetStructInt32PropertyImplementation(GarbageCollectionHandle, __Value, value);
		}

		private static uint __Value = 0;

		public nint GarbageCollectionHandle { get; set; }
	}
}

UObject

会生成反射变量，反射函数，接口函数和StaticClass等。

示例：UObject

C++

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "UnitTest/Core/TestInterface.h"
#include "TestReflectionPropertyActor.generated.h"

UCLASS()
class UNREALCSHARPTEST_API ATestReflectionPropertyActor : public AActor, public ITestInterface
{
	GENERATED_BODY()

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

public:
	UPROPERTY(BlueprintReadWrite)
	int32 Int32Value;
};

C#

using Script.Engine;
using Script.CoreUObject;
using Script.Library;

namespace Script.UnrealCSharpTest
{
    [PathName("/Script/UnrealCSharpTest.TestReflectionPropertyActor")]
    public partial class ATestReflectionPropertyActor : AActor, IStaticClass, ITestInterface
    {
        public int Int32Value
        {
            get => FPropertyImplementation.FProperty_GetObjectInt32PropertyImplementation(GarbageCollectionHandle， __Int32Value);

            set => FPropertyImplementation.FProperty_SetObjectInt32PropertyImplementation(GarbageCollectionHandle， __Int32Value, value);
        }

        public new static UClass StaticClass()
        {
            return UObjectImplementation.UObject_StaticClassImplementation("/Script/UnrealCSharpTest.TestReflectionPropertyActor");
        }

        private static uint __Int32Value = 0;
    }
}

模板

C++	C#
TScriptInterface	Script.CoreUObject.TScriptInterface`1
TSubclassOf	Script.CoreUObject.TSubclassOf`1
TWeakObjectPtr	Script.CoreUObject.TWeakObjectPtr`1
TLazyObjectPtr	Script.CoreUObject.TLazyObjectPtr`1
TSoftObjectPtr	Script.CoreUObject.TSoftObjectPtr`1
TSoftClassPtr	Script.CoreUObject.TSoftClassPtr`1
TOptional	Script.CoreUObject.TOptional`1

容器

C++	C#
TArray	Script.CoreUObject.TArray`1
TSet	Script.CoreUObject.TSet`1
TMap	Script.CoreUObject.TMap`2

代理

单播和多播都会映射为C#中的类，并且提供相关操作函数。

单播

示例：单播

C++

DECLARE_DYNAMIC_DELEGATE_RetVal_TwoParams(FEventReply, FOnPointerEvent, FGeometry, MyGeometry, const FPointerEvent&, MouseEvent);

C#

using System;
using Script.CoreUObject;
using Script.Library;
using Script.SlateCore;
using Script.UMG;

namespace Script.UMG.Widget
{
	public class FOnPointerEvent : FDelegate<Func<FGeometry, FPointerEvent, FEventReply>>
	{
		public FOnPointerEvent() => FDelegateImplementation.FDelegate_RegisterImplementation(this);

		~FOnPointerEvent() => FDelegateImplementation.FDelegate_UnRegisterImplementation(GarbageCollectionHandle);

		public FEventReply Execute(FGeometry MyGeometry, FPointerEvent MouseEvent)
		{
			return FDelegateImplementation.FDelegate_Execute3Implementation(GarbageCollectionHandle, MyGeometry, MouseEvent) as FEventReply;
		}
	}
}

多播

示例：多播

C++

DECLARE_DYNAMIC_MULTICAST_DELEGATE(FOnButtonClickedEvent);

C#

using System;
using Script.CoreUObject;
using Script.Library;

namespace Script.UMG
{
	public class FOnButtonClickedEvent : FMulticastDelegate<Action>
	{
		public FOnButtonClickedEvent() => FMulticastDelegateImplementation.FMulticastDelegate_RegisterImplementation(this);

		~FOnButtonClickedEvent() => FMulticastDelegateImplementation.FMulticastDelegate_UnRegisterImplementation(GarbageCollectionHandle);

		public void Broadcast()
		{
			FMulticastDelegateImplementation.FMulticastDelegate_Broadcast0Implementation(GarbageCollectionHandle);
		}
	}
}

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变量访问

对于C++或者蓝图中的反射变量，会生成对应的Properties，而非Fields，实际内存还是放在C++侧。

示例：变量访问

C++

#pragma once

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

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

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

public:
	UPROPERTY(BlueprintReadWrite)
	int32 Int32Value;
};

C#

using Script.CoreUObject;

namespace Script.UnrealCSharpTest
{
    public partial class UUnitTestSubsystem
    {
        private void TestReflectionProperty()
        {
            var PropertyActor = GetWorld().SpawnActor<ATestReflectionPropertyActor>(new FTransform());

            var Int32Value = PropertyActor.Int32Value;

            PropertyActor.Int32Value = 21;
        }
    }
}

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函数调用

对于C++或者蓝图中的反射函数，会生成对应的C#函数，并且处理好函数默认参数。

示例：函数调用

C++

#pragma once

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

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

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

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

	UFUNCTION(BlueprintCallable)
	int32 GetInt32ValueFunction() const;

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

C#

using Script.CoreUObject;
using Script.Engine;

namespace Script.UnrealCSharpTest
{
    public partial class UUnitTestSubsystem
    {
        private void TestReflectionFunction()
        {
            var FunctionActor = GetWorld().SpawnActor<ATestReflectionFunctionActor>(new FTransform());

            var Int32Value = FunctionActor.GetInt32ValueFunction();

            FunctionActor.SetInt32ValueFunction(21);

            var OutInt32Value = 12;

            FunctionActor.OutInt32ValueFunction(ref OutInt32Value);
        }
    }
}

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