RequiredMemberAttribute
Specifies that a type has required members or that a member is required.
using System.ComponentModel;
namespace System.Runtime.CompilerServices
{
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct | AttributeTargets.Property | AttributeTargets.Field, AllowMultiple = false, Inherited = false)]
[EditorBrowsable(EditorBrowsableState.Never)]
public sealed class RequiredMemberAttribute : Attribute
{
}
}