By default, all private readonly without initialization will be used. The will be injected with the same name without any leading _.
Fields marked with AutoConstructorIgnoreAttribute will be ignored.
Use AutoConstructorInjectAttribute to customize the behavior, usualy when the injected parameter and the fields
do not have the same type. It takes three parameters:
Initializer: a string that will be used to initialize the field (by example myService.GetData())
ParameterName: the name of the parameter to used in the constructor (by example myService)
InjectedType: the type of the parameter to used in the constructor (by example IMyService)
When using AutoConstructorInjectAttribute, the parameter name can be shared across multiple fields,
and even use a parameter from another field not annotated with AutoConstructorInjectAttribute, but type must match.
Configuration
By default, null checks with ArgumentNullException will be generated when needed.
To disable this behavior, set AutoConstructor_DisableNullChecking to false in the project file:
[AutoConstructor]
partial class Test
{
private readonly string _name;
// Won't be injected
private readonly Uri _uri = new Uri("/non-modified", UriKind.Relative);
// Won't be injected
[AutoConstructorIgnore]
private readonly DateTime _dateNotTaken;
// Won't be injected
private int? _toto;
// Support for nullables
private readonly DateTime? _date;
// Support for generics
private readonly List<DateTime> _items;
// Inject with custom initializer
[AutoConstructorInject("guid.ToString()", "guid", typeof(Guid))]
private readonly string _guidString;
// Use existing parameter defined with AutoConstructorInject
[AutoConstructorInject("guid.ToString().Length", "guid", typeof(Guid))]
private readonly int _guidLength;
// Use existing parameter from a basic injection
[AutoConstructorInject("name.ToUpper()", "name", typeof(string))]
private readonly string _nameShared;
}
will generate
public Test(string name, System.DateTime? date, System.Collections.Generic.List<System.DateTime> items, System.Guid guid)
{
this._name = name ?? throw new System.ArgumentNullException(nameof(name));
this._date = date ?? throw new System.ArgumentNullException(nameof(date));
this._items = items ?? throw new System.ArgumentNullException(nameof(items));
this._guidString = guid.ToString() ?? throw new System.ArgumentNullException(nameof(guid));
this._guidLength = guid.ToString().Length;
this._nameShared = name.ToUpper() ?? throw new System.ArgumentNullException(nameof(name));
}
Diagnostics
ACONS01
The AutoConstructor attribute is used on a class that is not partial.
ACONS02
The AutoConstructor attribute is used on a class without fiels to inject.
ACONS03
The AutoConstructorIgnore attribute is used on a field that won't already be processed.
ACONS04
The AutoConstructorInject attribute is used on a field that won't already be processed.
ACONS05
The AutoConstructorIgnore or AutoConstructorInject are used on a class without the AutoConstructor attribute.
ACONS06
A type specified in AutoConstructorInject attribute does not match the type of another parameter with the same name.
In the folowing sample, both fields will be injected with guid as parameter name, but one of type string and the other of type Guid,
preventing the generator from running.
public partial class Test
{
[AutoConstructorInject("guid.ToString()", "guid", typeof(Guid))]
private readonly string _guid2;
private readonly string _guid;
}
