RSCG – LightweightObjectMapper

name	LightweightObjectMapper
nuget	https://www.nuget.org/packages/LightweightObjectMapper/
link	https://github.com/stratosblue/LightweightObjectMapper
author	Stratos

Generating function to map DTOs

This is how you can use LightweightObjectMapper .

The code that you start with is


<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net8.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>

	<PropertyGroup>
		<EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>
		<CompilerGeneratedFilesOutputPath>$(BaseIntermediateOutputPath)\GX</CompilerGeneratedFilesOutputPath>
	</PropertyGroup>

	<ItemGroup>
	  <PackageReference Include="LightweightObjectMapper" Version="1.0.2" />
	</ItemGroup>

	<!--<PropertyGroup>
		<NoLightweightObjectMapperPreCodes>true</NoLightweightObjectMapperPreCodes>
		<LOMappingMethodAccessibility>public</LOMappingMethodAccessibility>
	</PropertyGroup>-->

	
</Project>

The code that you will use is


using mapperDemo;
using LightweightObjectMapper;
var p=new Person();
p.FirstName = "Andrei";
p.LastName = "Ignat";
PersonDTO dto= p.MapTo<PersonDTO>();
Console.WriteLine(dto.FullName);



public partial class Person
{
    public int ID { get; set; }
    public string? FirstName { get; set; }
    public string? LastName { get; set; }
}



namespace mapperDemo;
public partial class PersonDTO
{
    public int ID { get; set; }
    public string? FirstName { get; set; }
    public string? LastName { get; set; }
    public string FullName { 
        get
        {
            return FirstName + " " + LastName;
        }
    }
}


using LightweightObjectMapper;
using System;
namespace mapperDemo;

[MappingProfile]
internal partial class Extensions:
    IPostMapping<Person, PersonDTO>
{
    

    public PersonDTO PostMapping(Person source, PersonDTO target)
    {
        target.ID = source.ID;
        return target;
    }
}

The code that is generated is

// <Auto-Generated/>
#pragma warning disable IDE0005
#pragma warning disable CS0105
using LightweightObjectMapper;
using System;
using System;
using System.Linq;
using System.Runtime.CompilerServices;

namespace mapperDemo
{
    sealed partial class Extensions
    {
        public static partial class Generated
        {
            /// <summary>
            /// PostMappingDeclaration for <see cref = "global::Person"/> to <see cref = "global::mapperDemo.PersonDTO"/>
            /// </summary>
            [MethodImpl(MethodImplOptions.AggressiveInlining)]
            [MappingMetadata(MappingMetadataType.PostMappingDeclaration, typeof(global::Person), typeof(global::mapperDemo.PersonDTO))]
            public static global::mapperDemo.PersonDTO PostMapping_D275C37F33F4AFBD(global::Person source, global::mapperDemo.PersonDTO target)
            {
                target.ID = source.ID;
                return target;
            }
        }
    }
}

#if !NO_LIGHTWEIGHT_OBJECT_MAPPER_PRE_CODES

// <Auto-Generated/>

#pragma warning disable IDE0161 // 转换为文件范围限定的 namespace

using System;
using System.Collections.Generic;

namespace LightweightObjectMapper
{
    /// <summary>
    /// 映射配置接口
    /// </summary>
    internal interface IMappingProfile { }

    /// <summary>
    /// 映射后执行的动作
    /// </summary>
    /// <typeparam name="TIn"></typeparam>
    /// <typeparam name="TOut"></typeparam>
    internal interface IPostMapping<TIn, TOut> : IMappingProfile
    {
        /// <summary>
        /// 映射后执行的动作
        /// </summary>
        /// <param name="source"></param>
        /// <param name="target"></param>
        /// <returns></returns>
        TOut PostMapping(TIn source, TOut target);
    }

    /// <summary>
    /// 映射前准备
    /// </summary>
    /// <typeparam name="TIn"></typeparam>
    /// <typeparam name="TOut"></typeparam>
    internal interface IMappingPrepare<TIn, TOut> : IMappingProfile
    {
        /// <summary>
        /// 映射前准备
        /// </summary>
        /// <param name="source"></param>
        /// <returns></returns>
        TOut MappingPrepare(TIn source);
    }

    /// <summary>
    /// 接管完整的类型映射（仅非目标实例映射）
    /// </summary>
    /// <typeparam name="TIn"></typeparam>
    /// <typeparam name="TOut"></typeparam>
    internal interface ITypeMapping<TIn, TOut> : IMappingProfile
    {
        /// <summary>
        /// 接管完整的类型映射（仅非目标实例映射）
        /// </summary>
        /// <param name="source"></param>
        /// <returns></returns>
        TOut TypeMapping(TIn source);
    }

    /// <summary>
    /// 类型成员忽略映射
    /// </summary>
    /// <typeparam name="T"></typeparam>
    internal interface ITypeMemberIgnoreMapping<T> : IMappingProfile
    {
        /// <summary>
        /// 类型成员忽略映射<br/>
        /// 方法体内访问过的 <paramref name="target"/> 所有成员，将在映射时被忽略
        /// </summary>
        /// <param name="target"></param>
        /// <returns></returns>
        object? IgnoreMapping(T target);
    }

    /// <summary>
    /// 标记一个方法为集合映射方法<br/>
    /// 集合映射方法应包含唯一泛型参数 T ，以及唯一参数 <see cref="IEnumerable{T}"/> ，返回类型应该为 <see cref="IEnumerable{T}"/> 的派生类型
    /// </summary>
    [AttributeUsage(AttributeTargets.Method, Inherited = false, AllowMultiple = false)]
    internal sealed class CollectionMappingAttribute : Attribute
    {
    }

    /// <summary>
    /// 标记类为映射配置类
    /// </summary>
    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = false)]
    internal sealed class MappingProfileAttribute : Attribute
    {
        /// <inheritdoc cref="MappingProfileAttribute"/>
        public MappingProfileAttribute() { }
    }

    /// <summary>
    /// 映射元数据
    /// </summary>
    [AttributeUsage(AttributeTargets.All, Inherited = false, AllowMultiple = true)]
    internal sealed class MappingMetadataAttribute : Attribute
    {
        /// <inheritdoc cref="MappingMetadataAttribute"/>
        public MappingMetadataAttribute(MappingMetadataType type, params object[] data) { }
    }

    /// <summary>
    /// 映射元数据类型
    /// </summary>
    internal enum MappingMetadataType
    {
        /// <summary>
        /// 声明 MappingPrepare
        /// </summary>
        MappingPrepareDeclaration,

        /// <summary>
        /// 声明 PostMapping
        /// </summary>
        PostMappingDeclaration,

        /// <summary>
        /// 声明 TypeMapping
        /// </summary>
        TypeMappingDeclaration,

        /// <summary>
        /// 声明 CollectionMapping
        /// </summary>
        CollectionMappingDeclaration,

        /// <summary>
        /// 忽略成员声明
        /// </summary>
        IgnoreMembersDeclaration,

        /// <summary>
        /// 类型忽略成员声明
        /// </summary>
        TypeIgnoreMembersDeclaration,
    }

    /// <summary>
    /// 引用其它映射配置类
    /// </summary>
    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = true)]
    internal sealed class MappingProfileIncludeAttribute : Attribute
    {
        /// <inheritdoc cref="MappingProfileIncludeAttribute"/>
        public MappingProfileIncludeAttribute(params Type[] profileTypes) { }
    }

    /// <summary>
    /// 对象映射 MapTo 占位方法
    /// </summary>
    [Obsolete("Do not use the placeholder extension class.", true)]
    internal static class LightweightObjectMapperPlaceholderExtensions
    {
        private const string ErrorCallPlaceholderMethodMessage = "Do not use the placeholder extension method. If not redirect to the right mapper extension method please try fix other errors and rebuild the project.";

        /// <summary>
        /// 对象映射 MapTo 占位方法<br/>
        /// 生成 无需目标对象 的泛型映射方法，映射到 <typeparamref name="TOut"/>
        /// </summary>
        /// <typeparam name="TOut"></typeparam>
        /// <param name="source"></param>
        /// <returns></returns>
        [Obsolete(ErrorCallPlaceholderMethodMessage, true)]
        public static TOut MapTo<TOut>(this object source)
        {
            throw new NotImplementedException();
        }

        /// <summary>
        /// 对象映射 MapTo 占位方法<br/>
        /// 生成 需要目标对象 的泛型映射方法，映射到 <typeparamref name="TOut"/>
        /// </summary>
        /// <typeparam name="TOut"></typeparam>
        /// <param name="source"></param>
        /// <returns></returns>
        [Obsolete(ErrorCallPlaceholderMethodMessage, true)]
        public static TOut MapTo<TOut>(this object source, TOut target)
        {
            throw new NotImplementedException();
        }

        /// <summary>
        /// 值类型 对象映射 MapTo 占位方法<br/>
        /// 生成 需要目标值类型对象 的泛型映射方法，映射到 <typeparamref name="TOut"/>
        /// </summary>
        /// <typeparam name="TOut"></typeparam>
        /// <param name="source"></param>
        /// <returns></returns>
        [Obsolete(ErrorCallPlaceholderMethodMessage, true)]
        public static TOut MapTo<TOut>(this object source, ref TOut target)
            where TOut : struct
        {
            throw new NotImplementedException();
        }
    }
}

#endif

#if !NO_LIGHTWEIGHT_OBJECT_MAPPER_PRE_CODES

// <Auto-Generated/>

#pragma warning disable IDE0161 // 转换为文件范围限定的 namespace

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;

namespace LightweightObjectMapper
{
    /// <summary>
    /// 预定义的类型映射
    /// </summary>
    [MappingProfile]
    internal sealed partial class PredefinedSpecialTypeMapping
        : ITypeMapping<int, bool>
        , ITypeMapping<short, bool>
        , ITypeMapping<long, bool>
    {
        public bool TypeMapping(int source)
        {
            return source != 0;
        }

        public bool TypeMapping(short source)
        {
            return source != 0;
        }

        bool ITypeMapping<long, bool>.TypeMapping(long source)
        {
            return source != 0;
        }

        [CollectionMapping]
        public static IEnumerable<T>? ToIEnumerable<T>(IEnumerable<T>? items)
        {
            return items?.ToList();
        }

        [CollectionMapping]
        public static ICollection<T>? ToICollection<T>(IEnumerable<T>? items)
        {
            return items?.ToList();
        }

        [CollectionMapping]
        public static IReadOnlyCollection<T>? ToIReadOnlyCollection<T>(IEnumerable<T>? items)
        {
            return items?.ToList();
        }

        [CollectionMapping]
        public static IList<T>? ToIList<T>(IEnumerable<T>? items)
        {
            return items?.ToList();
        }

        [CollectionMapping]
        public static IReadOnlyList<T>? ToIReadOnlyList<T>(IEnumerable<T>? items)
        {
            return items?.ToList();
        }

        [CollectionMapping]
        public static List<T>? ToList<T>(IEnumerable<T>? items)
        {
            return items?.ToList();
        }
    }
}

#endif

// <Auto-Generated/>
#pragma warning disable IDE0005
#pragma warning disable CS0105
using System;
using System.Linq;
using System.Runtime.CompilerServices;

namespace LightweightObjectMapper
{
    internal static partial class LOMMapExtensions_mapperDemo
    {
        /// <summary>
        /// Map <see cref = "global::Person"/> to the following types:<br/>
        /// <see cref = "global::mapperDemo.PersonDTO"/><br/>
        /// </summary>
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static TOut MapTo<TOut>(this global::Person source)
        {
            if (source == null)
            {
                throw new ArgumentNullException(nameof(source));
            }

            if (typeof(TOut) == typeof(global::mapperDemo.PersonDTO))
            {
                var target = new global::mapperDemo.PersonDTO()
                {
                    LastName = source.LastName,
                    ID = source.ID,
                    FirstName = source.FirstName,
                };
                target = global::mapperDemo.Extensions.Generated.PostMapping_D275C37F33F4AFBD(source, target);
                return (TOut)(target as object);
            }

            throw new global::System.NotImplementedException($"No mapping code for {typeof(TOut)}.");
        }
    }
}

// <Auto-Generated/>
#pragma warning disable IDE0005
#pragma warning disable CS0105
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;
using System;
using System.Linq;
using System.Runtime.CompilerServices;

namespace LightweightObjectMapper
{
    sealed partial class PredefinedSpecialTypeMapping
    {
        public static partial class Generated
        {
            /// <summary>
            /// TypeMappingDeclaration for <see cref = "int "/> to <see cref = "bool "/>
            /// </summary>
            [MethodImpl(MethodImplOptions.AggressiveInlining)]
            [MappingMetadata(MappingMetadataType.TypeMappingDeclaration, typeof(int), typeof(bool))]
            public static bool TypeMapping_A07AFC9A322FFA04(int source)
            {
                return source != 0;
            }

            /// <summary>
            /// TypeMappingDeclaration for <see cref = "short "/> to <see cref = "bool "/>
            /// </summary>
            [MethodImpl(MethodImplOptions.AggressiveInlining)]
            [MappingMetadata(MappingMetadataType.TypeMappingDeclaration, typeof(short), typeof(bool))]
            public static bool TypeMapping_946949E7222BC174(short source)
            {
                return source != 0;
            }

            /// <summary>
            /// TypeMappingDeclaration for <see cref = "long "/> to <see cref = "bool "/>
            /// </summary>
            [MethodImpl(MethodImplOptions.AggressiveInlining)]
            [MappingMetadata(MappingMetadataType.TypeMappingDeclaration, typeof(long), typeof(bool))]
            public static bool TypeMapping_3C4D395B4EF43E87(long source)
            {
                return source != 0;
            }

            /// <summary>
            /// CollectionMappingDeclaration for <see cref = "global::System.Collections.Generic.IEnumerable{T}"/>
            /// </summary>
            [MethodImpl(MethodImplOptions.AggressiveInlining)]
            [MappingMetadata(MappingMetadataType.CollectionMappingDeclaration, typeof(global::System.Collections.Generic.IEnumerable<>))]
            public static global::System.Collections.Generic.IEnumerable<T> CollectionMapping_CEFAD35E246FD0F7<T>(global::System.Collections.Generic.IEnumerable<T> items)
            {
                return items?.ToList();
            }

            /// <summary>
            /// CollectionMappingDeclaration for <see cref = "global::System.Collections.Generic.ICollection{T}"/>
            /// </summary>
            [MethodImpl(MethodImplOptions.AggressiveInlining)]
            [MappingMetadata(MappingMetadataType.CollectionMappingDeclaration, typeof(global::System.Collections.Generic.ICollection<>))]
            public static global::System.Collections.Generic.ICollection<T> CollectionMapping_37FFD1A2226B51E9<T>(global::System.Collections.Generic.IEnumerable<T> items)
            {
                return items?.ToList();
            }

            /// <summary>
            /// CollectionMappingDeclaration for <see cref = "global::System.Collections.Generic.IReadOnlyCollection{T}"/>
            /// </summary>
            [MethodImpl(MethodImplOptions.AggressiveInlining)]
            [MappingMetadata(MappingMetadataType.CollectionMappingDeclaration, typeof(global::System.Collections.Generic.IReadOnlyCollection<>))]
            public static global::System.Collections.Generic.IReadOnlyCollection<T> CollectionMapping_AF82A9960EE0C495<T>(global::System.Collections.Generic.IEnumerable<T> items)
            {
                return items?.ToList();
            }

            /// <summary>
            /// CollectionMappingDeclaration for <see cref = "global::System.Collections.Generic.IList{T}"/>
            /// </summary>
            [MethodImpl(MethodImplOptions.AggressiveInlining)]
            [MappingMetadata(MappingMetadataType.CollectionMappingDeclaration, typeof(global::System.Collections.Generic.IList<>))]
            public static global::System.Collections.Generic.IList<T> CollectionMapping_284BCB723CA17B0E<T>(global::System.Collections.Generic.IEnumerable<T> items)
            {
                return items?.ToList();
            }

            /// <summary>
            /// CollectionMappingDeclaration for <see cref = "global::System.Collections.Generic.IReadOnlyList{T}"/>
            /// </summary>
            [MethodImpl(MethodImplOptions.AggressiveInlining)]
            [MappingMetadata(MappingMetadataType.CollectionMappingDeclaration, typeof(global::System.Collections.Generic.IReadOnlyList<>))]
            public static global::System.Collections.Generic.IReadOnlyList<T> CollectionMapping_976EA1DB5B772C59<T>(global::System.Collections.Generic.IEnumerable<T> items)
            {
                return items?.ToList();
            }

            /// <summary>
            /// CollectionMappingDeclaration for <see cref = "global::System.Collections.Generic.List{T}"/>
            /// </summary>
            [MethodImpl(MethodImplOptions.AggressiveInlining)]
            [MappingMetadata(MappingMetadataType.CollectionMappingDeclaration, typeof(global::System.Collections.Generic.List<>))]
            public static global::System.Collections.Generic.List<T> CollectionMapping_070F0D0F908DAF14<T>(global::System.Collections.Generic.IEnumerable<T> items)
            {
                return items?.ToList();
            }
        }
    }
}

Code and pdf at

https://ignatandrei.github.io/RSCG_Examples/v2/docs/LightweightObjectMapper

RSCG – LightweightObjectMapper

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