Question

Attribute code

[AttributeUsage(AttributeTargets.Property, Inherited = true)]
class IgnoreAttribute : Attribute
{
}

Base class

abstract class ManagementUnit
{
    [Ignore]
    public abstract byte UnitType { get; }
}

Main class

class Region : ManagementUnit
{
    public override byte UnitType
    {
        get { return 0; }
    }

    private static void Main()
    {
        Type t = typeof(Region);
        foreach (PropertyInfo p in t.GetProperties())
        {
            if (p.GetCustomAttributes(typeof(IgnoreAttribute), true).Length != 0)
                Console.WriteLine("have attr");
            else
                Console.WriteLine("don't have attr");
        }
    }
}

Output: don't have attr

Explain why this is happening? After all, it must inherited.

Answer 1

The inherited flag dictates whether the attribute can be inherited.
The default for this value is false. However, if the inherited flag is
set to true, its meaning depends on the value of the AllowMultiple
flag. If the inherited flag is set to true and the AllowMultiple flag
is false, the attribute will override the inherited attribute.
However, if the inherited flag is set to true and the AllowMultiple
flag is also set to true, the attribute accumulates on the member.

from http://aclacl.brinkster.net/InsideC/32ch09f.htm
Check the chapter Specifying Inheritance Attribute Rules

EDIT: check Inheritance of Custom Attributes on Abstract Properties
The first answer:

It’s the GetCustomAttributes() method that does not look at parent
declarations. It only looks at attributes applied to the specified
member.