Create custom ObsoleteAttribute in C#

Question

I'd like to use a ObsoleteAttribute with a custom const message in order to avoid copy/pasting the message everywhere. For example here is my class:

[AttributeUsage(AttributeTargets.Property)]
public class MyObsoleteAttribute : Attribute
{
    private const string CustomMessage = "This is a custom warning message";
    public MyObsoleteAttribute()
    {
        Console.WriteLine(CustomMessage);
    }
}
    
public class MyClass
{
    [MyObsolete]
    public string? Foo { get; set; }
    
    [MyObsolete]
    public string? Bar { get; set; }
    
    [MyObsolete]
    public string? FooBar { get; set; }
}

I'd like to receive a warning in JetBrains Rider (or Visual Studio) when using such property in the same way as the Obsolete attribute with my CustomMessage.

I try overriding ObsoleteAttribute but it is sealed.

For example the following code should raise a warning (compile time) telling me "This is a custom warning message".

var myClass = new MyClass();
var foo = myClass.Foo;
var bar = myClass.Bar;
var fooBar = myClass.FooBar;

I looked here but I couldn't find exactly an answer to this case: the closest answer is this but it gives me warning on the property and not when using them.

Answer 1

You could define a string constant

public class ObsoleteReasons
{
    public const string Reason1 = "Don't use this";
}

and use it in the attribute

[Obsolete(ObsoleteReasons.Reason1)]