Introduce a "OnChangedMethod" attribute

class MyClass : INotifyPropertyChanged 
{
    [OnChangedMethod(nameof(OnMyPropertyChanged))]
    int MyProperty { get; set; }

    void OnMyPropertyChanged()
    {
    }
}

Since we have a nameof operator today, we could decorate the property with a “link” to the on changed method. This will avoid the problems with renaming, and omit the compiler warnings that OnMyPropertyChanged is never used. It also will allow direct navigation to the method from the property.

This attribute would be optional, for those who like to use it. To be fully backward compatible, the weaver would only check that, if the attribute is present, the name of the method matches the desired pattern.

#447 could then also give a hint to properly decorate the property.

[ltrzesniewski]

It would need a few changes but not that much (basically adding the method info to PropertyData).

Also, we could allow the user to provide multiple OnChangedMethod attributes, to call multiple methods when a property changes.

[ltrzesniewski]

It wasn’t that bad. I made a draft that I will need to rebase in #464.

It enables stuff like that:

https://github.com/Fody/PropertyChanged/blob/aef044d5d7487de3b776e2df8a69284b21ce9192/TestAssemblies/AssemblyToProcess/ClassWithOnChangedCustomized.cs#L10-L12