AutoCtor

AutoCtor is a Roslyn Source Generator that will automatically create a constructor for your class for use with constructor Dependency Injection.

+[AutoConstruct]
public partial class AService
{
private readonly IDataContext _dataContext;
private readonly IDataService _dataService;
private readonly IExternalService _externalService;
private readonly ICacheService _cacheService;
private readonly ICacheProvider _cacheProvider;
private readonly IUserService _userService;
- public AService(- IDataContext dataContext,- IDataService dataService,- IExternalService externalService,- ICacheService cacheService,- ICacheProvider cacheProvider,- IUserService userService- )- {- _dataContext = dataContext;- _dataService = dataService;- _externalService = externalService;- _cacheService = cacheService;- _cacheProvider = cacheProvider;- _userService = userService;- }
}

Contents

• NuGet packages
• Code Fixes (new in 3.0)
• Examples
  • Basic
  • Inherited
  • Properties
• Post Constructor Initialization
  • Extra Parameters
  • out/ref Parameters
  • Optional Parameters
• Argument Guards
• Keyed Services
• Other
  • Embedding The Attributes
  • Keeping Attributes In Code
• Star History
• Stats

NuGet packages

https://nuget.org/packages/AutoCtor/

Code Fixes (new in 3.0)

Starting in version 3.0, a new diagnostic has been introduced: ACTR007 Use [AutoConstruct] instead of manual constructor. This will appear on constructors that can be automatically converted to use [AutoConstruct]. A code fix is also available to perform the conversion automatically.

In 3.1 another code fix was added: Add [AutoConstruct] to type. This will add [AutoConstruct] to a type with no constructor and relevant fields. This is useful when working on a new type.

Examples

Basic

[AutoConstruct]publicpartialclassBasic{privatereadonlyIService_service;privatereadonlyIList<string>_list=newList<string>();}

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What gets generated

//HintName: Basic.g.cs//------------------------------------------------------------------------------// <auto-generated>// This code was generated by https://github.com/distantcam/AutoCtor// </auto-generated>//------------------------------------------------------------------------------partialclassBasic{[global::System.Runtime.CompilerServices.CompilerGenerated][global::System.CodeDom.Compiler.GeneratedCode("AutoCtor","0.0.0.0")][global::System.Diagnostics.DebuggerNonUserCode][global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]publicBasic(global::IServiceservice){this._service=service;}}

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Inherited

publicabstractclassBaseClass{protectedIAnotherService_anotherService;publicBaseClass(IAnotherServiceanotherService){_anotherService=anotherService;}}[AutoConstruct]publicpartialclassInherited:BaseClass{privatereadonlyIService_service;}

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What gets generated

//HintName: Inherited.g.cs//------------------------------------------------------------------------------// <auto-generated>// This code was generated by https://github.com/distantcam/AutoCtor// </auto-generated>//------------------------------------------------------------------------------partialclassInherited{[global::System.Runtime.CompilerServices.CompilerGenerated][global::System.CodeDom.Compiler.GeneratedCode("AutoCtor","0.0.0.0")][global::System.Diagnostics.DebuggerNonUserCode][global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]publicInherited(global::IAnotherServiceanotherService,global::IServiceservice):base(anotherService){this._service=service;}}

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Properties

// AutoCtor will initialize thesepublicstringGetProperty{get;}protectedstringProtectedProperty{get;}publicstringInitProperty{get;init;}publicrequiredstringRequiredProperty{get;set;}// AutoCtor will ignore thesepublicstringInitializerProperty{get;}="Constant";publicstringGetSetProperty{get;set;}publicstringFixedProperty=> "Constant";publicstringRedirectedProperty=> InitializerProperty;

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What gets generated

//HintName: Properties.g.cs//------------------------------------------------------------------------------// <auto-generated>// This code was generated by https://github.com/distantcam/AutoCtor// </auto-generated>//------------------------------------------------------------------------------partialclassProperties{[global::System.Runtime.CompilerServices.CompilerGenerated][global::System.CodeDom.Compiler.GeneratedCode("AutoCtor","0.0.0.0")][global::System.Diagnostics.DebuggerNonUserCode][global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]publicProperties(stringgetProperty,stringprotectedProperty,stringinitProperty,stringrequiredProperty){this.GetProperty=getProperty;this.ProtectedProperty=protectedProperty;this.InitProperty=initProperty;this.RequiredProperty=requiredProperty;}}

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Post Constructor Initialization

You can mark a method to be called at the end of the constructor with the attribute [AutoPostConstruct]. This method must return void.

[AutoConstruct]publicpartialclassPostConstruct{privatereadonlyIService_service;[AutoPostConstruct]privatevoidInitialize(){}}

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What gets generated

//HintName: PostConstruct.g.cs//------------------------------------------------------------------------------// <auto-generated>// This code was generated by https://github.com/distantcam/AutoCtor// </auto-generated>//------------------------------------------------------------------------------partialclassPostConstruct{[global::System.Runtime.CompilerServices.CompilerGenerated][global::System.CodeDom.Compiler.GeneratedCode("AutoCtor","0.0.0.0")][global::System.Diagnostics.DebuggerNonUserCode][global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]publicPostConstruct(global::IServiceservice){this._service=service;Initialize();}}

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Extra Parameters

Post construct methods can also take parameters. The generated constructor will include these parameters.

[AutoConstruct]publicpartialclassPostConstructWithParameter{privatereadonlyIService_service;[AutoPostConstruct]privatevoidInitialize(IInitializeServiceinitialiseService){}}

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What gets generated

//HintName: PostConstructWithParameter.g.cs//------------------------------------------------------------------------------// <auto-generated>// This code was generated by https://github.com/distantcam/AutoCtor// </auto-generated>//------------------------------------------------------------------------------partialclassPostConstructWithParameter{[global::System.Runtime.CompilerServices.CompilerGenerated][global::System.CodeDom.Compiler.GeneratedCode("AutoCtor","0.0.0.0")][global::System.Diagnostics.DebuggerNonUserCode][global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]publicPostConstructWithParameter(global::IServiceservice,global::IInitializeServiceinitialiseService){this._service=service;Initialize(initialiseService);}}

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out/ref Parameters

Parameters marked with out or ref are set back to any fields that match the same type. This can be used to set readonly fields with more complex logic.

[AutoConstruct]publicpartialclassPostConstructWithOutParameter{privatereadonlyIService_service;privatereadonlyIOtherService_otherService;[AutoPostConstruct]privatevoidInitialize(IServiceProviderservices,outIServiceservice){service=services.GetService<IService>();}}

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What gets generated

//HintName: PostConstructWithOutParameter.g.cs//------------------------------------------------------------------------------// <auto-generated>// This code was generated by https://github.com/distantcam/AutoCtor// </auto-generated>//------------------------------------------------------------------------------partialclassPostConstructWithOutParameter{[global::System.Runtime.CompilerServices.CompilerGenerated][global::System.CodeDom.Compiler.GeneratedCode("AutoCtor","0.0.0.0")][global::System.Diagnostics.DebuggerNonUserCode][global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]publicPostConstructWithOutParameter(global::IOtherServiceotherService,global::IServiceProviderservices){this._otherService=otherService;Initialize(services,outthis._service);}}

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Optional Parameters

[AutoConstruct]publicpartialclassPostConstructWithDefaultParameter{[AutoPostConstruct]privatevoidInitialize(Service?service=default){}}

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What gets generated

//HintName: PostConstructWithDefaultParameter.g.cs//------------------------------------------------------------------------------// <auto-generated>// This code was generated by https://github.com/distantcam/AutoCtor// </auto-generated>//------------------------------------------------------------------------------partialclassPostConstructWithDefaultParameter{[global::System.Runtime.CompilerServices.CompilerGenerated][global::System.CodeDom.Compiler.GeneratedCode("AutoCtor","0.0.0.0")][global::System.Diagnostics.DebuggerNonUserCode][global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]publicPostConstructWithDefaultParameter(global::Serviceservice=default){Initialize(service);}}

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Argument Guards

Null guards for the arguments to the constructor can be added in 2 ways.

In your project you can add a AutoCtorGuards property.

<ProjectSdk="Microsoft.NET.Sdk">
<PropertyGroup>
<AutoCtorGuards>true</AutoCtorGuards>
</PropertyGroup>
</Project>

OR

In each AutoConstruct attribute you can add a setting to enable/disable guards.

[AutoConstruct(GuardSetting.Enabled)]publicpartialclassGuarded{privatereadonlyIService_service;}

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What gets generated

//HintName: Guarded.g.cs//------------------------------------------------------------------------------// <auto-generated>// This code was generated by https://github.com/distantcam/AutoCtor// </auto-generated>//------------------------------------------------------------------------------partialclassGuarded{[global::System.Runtime.CompilerServices.CompilerGenerated][global::System.CodeDom.Compiler.GeneratedCode("AutoCtor","0.0.0.0")][global::System.Diagnostics.DebuggerNonUserCode][global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]publicGuarded(global::IServiceservice){this._service=service??thrownewglobal::System.ArgumentNullException("service");}}

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Keyed Services

When using Microsoft.Extensions.DependencyInjection you can mark fields and properties with [AutoKeyedService] and it will be included in the constructor.

[AutoConstruct]publicpartialclassKeyed{[AutoKeyedService("key")]privatereadonlyIService_keyedService;}

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What gets generated

//HintName: Keyed.g.cs//------------------------------------------------------------------------------// <auto-generated>// This code was generated by https://github.com/distantcam/AutoCtor// </auto-generated>//------------------------------------------------------------------------------partialclassKeyed{[global::System.Runtime.CompilerServices.CompilerGenerated][global::System.CodeDom.Compiler.GeneratedCode("AutoCtor","0.0.0.0")][global::System.Diagnostics.DebuggerNonUserCode][global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]publicKeyed([global::Microsoft.Extensions.DependencyInjection.FromKeyedServices("key")]global::IServicekeyedService){this._keyedService=keyedService;}}

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Other

Embedding The Attributes

By default, the [AutoConstruct] attributes referenced in your project are contained in an external dll. It is also possible to embed the attributes directly in your project. To do this, you must do two things:

1. Define the constant AUTOCTOR_EMBED_ATTRIBUTES. This ensures the attributes are embedded in your project.
2. Add compile to the list of excluded assets in your <PackageReference> element. This ensures the attributes in your project are referenced, instead of the AutoCtor.Attributes.dll library.

Your project file should look like this:

<ProjectSdk="Microsoft.NET.Sdk">
<PropertyGroup>
<!-- Define the MSBuild constant -->
<DefineConstants>$(DefineConstants);AUTOCTOR_EMBED_ATTRIBUTES</DefineConstants>
</PropertyGroup>
<!-- Add the package -->
<PackageReferenceInclude="AutoCtor"PrivateAssets="all"ExcludeAssets="compile;runtime" />
<!-- ☝ Add compile to the list of excluded assets. -->
</Project>

What gets generated

//HintName: AutoConstructAttribute.g.cs//------------------------------------------------------------------------------// <auto-generated>// This code was generated by https://github.com/distantcam/AutoCtor// </auto-generated>//------------------------------------------------------------------------------
#if AUTOCTOR_EMBED_ATTRIBUTESnamespaceAutoCtor{[global::System.Runtime.CompilerServices.CompilerGenerated][global::System.CodeDom.Compiler.GeneratedCode("AutoCtor","0.0.0.0")]internalenumGuardSetting{Default,Disabled,Enabled}[global::System.Runtime.CompilerServices.CompilerGenerated][global::System.CodeDom.Compiler.GeneratedCode("AutoCtor","0.0.0.0")][global::System.Diagnostics.DebuggerNonUserCode][global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage][global::System.AttributeUsage(global::System.AttributeTargets.Class|global::System.AttributeTargets.Struct,AllowMultiple=false,Inherited=false)]internalsealedclassAutoConstructAttribute:global::System.Attribute{publicAutoConstructAttribute(GuardSettingguard=GuardSetting.Default){}}[global::System.Runtime.CompilerServices.CompilerGenerated][global::System.CodeDom.Compiler.GeneratedCode("AutoCtor","0.0.0.0")][global::System.Diagnostics.DebuggerNonUserCode][global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage][global::System.AttributeUsage(global::System.AttributeTargets.Method,AllowMultiple=false,Inherited=false)]internalsealedclassAutoPostConstructAttribute:global::System.Attribute{}[global::System.Runtime.CompilerServices.CompilerGenerated][global::System.CodeDom.Compiler.GeneratedCode("AutoCtor","0.0.0.0")][global::System.Diagnostics.DebuggerNonUserCode][global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage][global::System.AttributeUsage(global::System.AttributeTargets.Field|global::System.AttributeTargets.Property,AllowMultiple=false,Inherited=false)]internalsealedclassAutoConstructIgnoreAttribute:global::System.Attribute{}[global::System.Runtime.CompilerServices.CompilerGenerated][global::System.CodeDom.Compiler.GeneratedCode("AutoCtor","0.0.0.0")][global::System.Diagnostics.DebuggerNonUserCode][global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage][global::System.AttributeUsage(global::System.AttributeTargets.Field|global::System.AttributeTargets.Property|global::System.AttributeTargets.Parameter,AllowMultiple=false,Inherited=false)]internalsealedclassAutoKeyedServiceAttribute:global::System.Attribute{publicobjectKey{get;}publicAutoKeyedServiceAttribute(objectkey)=>Key=key;}}
#endif

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Keeping Attributes In Code

The [AutoConstruct] attributes are decorated with the [Conditional] attribute, so their usage will not appear in the build output of your project. If you use reflection at runtime you will not find the [AutoConstruct] attributes.

If you wish to preserve these attributes in the build output, add the define constant AUTOCTOR_USAGES.

<ProjectSdk="Microsoft.NET.Sdk">
<PropertyGroup>
<!-- Define the MSBuild constant -->
<DefineConstants>$(DefineConstants);AUTOCTOR_USAGES</DefineConstants>
</PropertyGroup>
</Project>

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