Class AspectAttribute

Defines an abstract aspect that can be applied against service interfaces or classes. Aspects are the prefered way to decorate service instances.

// Base class of all the validator attributes
public abstract class ParameterValidatorAttribute : Attribute
{
    public abstract void Validate(ParameterInfo param, object value);
}
...
// Sample validator
[AttributeUsage(AttributeTargets.Parameter, AllowMultiple = false)]
public class NotNullAttribute : ParameterValidatorAttribute
{
    public override void Validate(ParameterInfo param, object value)
    {
        if (value is null)
            throw new ArgumentNullException(param.Name);
    }
}
...
public class ParameterValidatorProxy : IInterfaceInterceptor
{
    public ParameterValidator(IDependency dependency) {...}

    public object? Invoke(IInvocationContext context, CallNextDelegate<IInvocationContext?, object> callNext)
    {
        foreach (var descr in context.TargetMethod.GetParameters().Select
        (
            (p, i) => new
            {
                Parameter = p,
                Value = context.Args[i],
                Validators = p.GetCustomAttributes<ParameterValidatorAttribute>()
            }
        ))
        {
            foreach (var validator in descr.Validators)
            {
                validator.Validate(descr.Parameter, descr.Value);
            }
        }
        return callNext(context);
    }
}
...
// Define the comcrete aspect
[AttributeUsage(AttributeTargets.Interface | AttributeTargets.Class, AllowMultiple = false)]
public sealed class ParameterValidatorAspect : AspectAttribute
{
    public ParameterValidatorAspect(): base(typeof(ParameterValidatorProxy)) { }
}
// Then annotate the desired interface ...
[ParameterValidatorAspect]
public interface IService
{
void DoSomething([NotNull] object arg);
}

// ... OR class (recommended)

[ParameterValidatorAspect]
public class Service : IService
{
    // Only methods implementing the above declared interface can be annoteted 
    void DoSomething([NotNull] object arg) { ...}
}

Inheritance

System.Object

AspectAttribute

Namespace: Solti.Utils.DI.Interfaces

Assembly: Solti.Utils.DI.Interfaces.dll

Syntax

public class AspectAttribute : Attribute

Remarks

Constructors

AspectAttribute(Expression<CreateInterceptorDelegate>)

Creates a new AbstractServiceEntry instance.

Declaration

public AspectAttribute(Expression<CreateInterceptorDelegate> factory)

Parameters

Type	Name	Description
System.Linq.Expressions.Expression<CreateInterceptorDelegate>	factory

AspectAttribute(Type)

Creates a new AbstractServiceEntry instance.

Declaration

public AspectAttribute(Type interceptor)

Parameters

Type	Name	Description
System.Type	interceptor

AspectAttribute(Type, Object)

Creates a new AbstractServiceEntry instance.

Declaration

public AspectAttribute(Type interceptor, object explicitArgs)

Parameters

Type	Name	Description
System.Type	interceptor
System.Object	explicitArgs

Properties

ExplicitArgs

Explicit arguments to be passed:

new {ctorParamName1 = ..., ctorParamName2 = ...}

Declaration

public object ExplicitArgs { get; }

Property Value

Type	Description
System.Object

Factory

Factory function responsible for creating the concrete interceptor.

Declaration

public Expression<CreateInterceptorDelegate> Factory { get; }

Property Value

Type	Description
System.Linq.Expressions.Expression<CreateInterceptorDelegate>

Interceptor

The underlying interceptor.

Declaration

public Type Interceptor { get; }

Property Value

Type	Description
System.Type

Remarks

This type must be a class that can be instantiated and implements the IInterfaceInterceptor interface.