Generic attributes

One of the limitations of C# attributes that we used to have is that attributes could not be generic types taking generic arguments. Prior to C# 11, you would get a compiler error if you added a generic argument to your attribute class. This limitation is lifted with the release of C# 11.

Up till C# 11, the only way you could collect type information was for the attribute to have parameters or properties that were of type System.Type. This became very verbose:

public class CustomAttribute : Attribute
{
    public CustomAttribute(Type theType)
}

And then adorning a type with the attribute would be as follows:

[Custom(typeof(string))]
public class MyClass
{
}

With C# 11, now you can improve how you get type information:

public class CustomAttribute<T> : Attribute
{
}

When you adorn a type with the attribute, you use the generic argument:

[Custom<string>]
public class MyClass
{
}

If you’re looking to...