DotNetBrightener.Mapper.Attributes 2026.0.2

DotNetBrightener.Mapper.Attributes

Copyright © 2017 - 2026 Vampire Coder (formerly DotnetBrightener)

DotNetBrightener.Mapper.Attributes contains the runtime attribute and enum definitions used by the DotNetBrightener.Mapper source generator ecosystem.

This package does not contain the generator itself. It provides the attribute types that your application code references.

Install

If you are using the full mapper package, you typically do not need to install this package directly.

dotnet add package DotNetBrightener.Mapper

Install DotNetBrightener.Mapper.Attributes directly only if you specifically want the attribute definitions without bringing in the full generator package:

dotnet add package DotNetBrightener.Mapper.Attributes

Namespace

using DotNetBrightener.Mapper;

Included Attributes

This package currently exposes:

• MappingTargetAttribute<TSource>
• FlattenAttribute
• MapFromAttribute
• MapWhenAttribute
• GenerateDtosAttribute
• WrapperAttribute

It also includes these enums:

• DtoTypes
• OutputType
• FlattenNamingStrategy

MappingTarget<TSource>

Use MappingTarget<TSource> to generate a target type from a source type.

[MappingTarget<User>(GenerateToSource = true)]
public partial class UserDto;

Common options include:

• Exclude
• Include
• IncludeFields
• GenerateConstructor
• GenerateParameterlessConstructor
• GenerateProjection
• GenerateToSource
• Configuration
• BeforeMapConfiguration
• AfterMapConfiguration
• NestedTargetTypes
• FlattenTo
• NullableProperties
• PreserveInitOnlyProperties
• PreserveRequiredProperties
• PreserveReferences
• MaxDepth
• ConvertEnumsTo
• GenerateCopyConstructor
• GenerateEquality
• ChainToParameterlessConstructor
• CopyAttributes
• UseFullName
• SourceSignature

Example with exclusions and nested targets:

[MappingTarget<Order>(
    nameof(Order.InternalNotes),
    GenerateToSource = true,
    NestedTargetTypes = [typeof(OrderItemDto), typeof(AddressDto)])]
public partial class OrderDto;

Flatten

Use Flatten to generate flattened output types from nested object graphs.

[Flatten(typeof(Order))]
public partial class OrderExportRow;

Useful options include:

• Exclude
• MaxDepth
• NamingStrategy
• IncludeFields
• GenerateParameterlessConstructor
• GenerateProjection
• UseFullName
• IgnoreNestedIds
• IgnoreForeignKeyClashes
• IncludeCollections

MapFrom

Use MapFrom on target members to map from a different source member or expression.

[MappingTarget<User>]
public partial class UserDto
{
    [MapFrom(nameof(User.DisplayName))]
    public string Name { get; set; } = string.Empty;

    [MapFrom("FirstName + \" \" + LastName", Reversible = false)]
    public string FullName { get; set; } = string.Empty;
}

Key options:

• Source
• Reversible
• IncludeInProjection

MapWhen

Use MapWhen to conditionally map a target member.

[MappingTarget<Order>]
public partial class OrderDto
{
    [MapWhen("Status == OrderStatus.Completed")]
    public DateTime? CompletedAt { get; set; }
}

Key options:

• Condition
• Default
• IncludeInProjection

GenerateDtos

Use GenerateDtos to generate common DTO shapes from a model.

[GenerateDtos(
    Types = DtoTypes.Create | DtoTypes.Update | DtoTypes.Response,
    OutputType = OutputType.Record,
    ExcludeAuditFields = true)]
public partial class User;

Supported configuration includes:

• Types
• OutputType
• Namespace
• ExcludeProperties
• ExcludeAuditFields
• Prefix
• Suffix
• IncludeFields
• GenerateConstructors
• GenerateProjections
• UseFullName

Wrapper

Use Wrapper to generate a delegating wrapper around an existing source type instead of copying values into a separate target object.

[Wrapper(typeof(User), nameof(User.PasswordHash))]
public partial class UserWrapper;

Supported configuration includes:

• constructor sourceType
• constructor exclude
• Include
• IncludeFields
• ReadOnly
• NestedWrappers
• CopyAttributes
• UseFullName

AOT And Runtime Safety

This package is runtime-safe and lightweight because it contains only attribute and enum definitions. Keeping these definitions separate from the generator avoids pulling Roslyn dependencies into application runtime deployments, including AOT scenarios.