mono/netcore/System.Private.CoreLib/shared/System/Reflection/DefaultMemberAttribute.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

namespace System.Reflection
{
    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct | AttributeTargets.Interface)]
    public sealed class DefaultMemberAttribute : Attribute
    {
        // You must provide the name of the member, this is required
        public DefaultMemberAttribute(string memberName)
        {
            MemberName = memberName;
        }

        // A get accessor to return the name from the attribute.
        // NOTE: There is no setter because the name must be provided
        //    to the constructor.  The name is not optional.
        public string MemberName { get; }
    }
}