| Severity | Error |
| Reported by | PostSharp |
| Message | The call to AspectUtilities.InitializeCurrentAspects in type "<CallingType>" cannot invoke the method "<Method>" because this method is private. Make this method protected. |
Cause
PostSharp replaces each call to InitializeCurrentAspects() with a call to the InitializeAspects method of the current object. It looks for this method in the class that contains the call, and then in its base classes. You can declare InitializeAspects yourself, typically in the root class of a hierarchy, so that the aspects of all the derived classes can be initialized when an object is created without a constructor.
When the method that PostSharp finds is private and declared in a base class, the calling class cannot invoke it, and PostSharp reports LA0045. <Method> is the InitializeAspects method of the base class, and <CallingType> is the class that contains the call to InitializeCurrentAspects(). The message is reported on the line of the call.
In the following example, EntityBase declares a private InitializeAspects method, and the derived Customer class calls InitializeCurrentAspects().
using System;
using PostSharp.Aspects;
using PostSharp.Serialization;
namespace Errors.LA0045_Error;
[PSerializable]
public sealed class LogAttribute : OnMethodBoundaryAspect
{
public override void OnEntry( MethodExecutionArgs args ) => Console.WriteLine( $"Entering {args.Method.Name}." );
}
public abstract class EntityBase
{
// The method is private, so the derived classes cannot call it.
private void InitializeAspects()
{
Console.WriteLine( $"Initializing the aspects of {this.GetType().Name}." );
}
}
public class Customer : EntityBase
{
public string? Name { get; set; }
[Log]
public void Greet() => Console.WriteLine( $"Hello, {this.Name}." );
// Called by a custom deserializer, which does not call the constructor.
public void OnRestored() => AspectUtilities.InitializeCurrentAspects();
}
public static class Program
{
public static void Main()
{
var customer = new Customer { Name = "Alice" };
customer.OnRestored();
customer.Greet();
}
}
error LA0045: LA0045_Error.cs(30,33): The call to AspectUtilities.InitializeCurrentAspects in type "Errors.LA0045_Error.Customer" cannot invoke the method "Errors.LA0045_Error.EntityBase.InitializeAspects" because this method is private. Make this method protected.
Resolution
Declare InitializeAspects as protected virtual void InitializeAspects(), as described in Coping with Custom Object Serializers. A protected method can be called from the derived classes, and a virtual method lets PostSharp override it in the derived classes that have aspects. The article also lists the other constraints on this method.
In the following example, InitializeAspects is protected and virtual, so the call in Customer reaches it.
using System;
using PostSharp.Aspects;
using PostSharp.Serialization;
namespace Errors.LA0045_Fixed;
[PSerializable]
public sealed class LogAttribute : OnMethodBoundaryAspect
{
public override void OnEntry( MethodExecutionArgs args ) => Console.WriteLine( $"Entering {args.Method.Name}." );
}
public abstract class EntityBase
{
// The method is protected and virtual, so the derived classes can call and extend it.
protected virtual void InitializeAspects()
{
Console.WriteLine( $"Initializing the aspects of {this.GetType().Name}." );
}
}
public class Customer : EntityBase
{
public string? Name { get; set; }
[Log]
public void Greet() => Console.WriteLine( $"Hello, {this.Name}." );
// Called by a custom deserializer, which does not call the constructor.
public void OnRestored() => AspectUtilities.InitializeCurrentAspects();
}
public static class Program
{
public static void Main()
{
var customer = new Customer { Name = "Alice" };
customer.OnRestored();
customer.Greet();
}
}
Initializing the aspects of Customer.
Entering Greet.
Hello, Alice.
See Also
Reference
Other Resources