Convert IEnumerable To ReadOnlyCollection : IEnumerable « Collections Data Structure « C# / C Sharp

1. C# / C Sharp
2. Collections Data Structure
3. IEnumerable

Convert IEnumerable To ReadOnlyCollection

  

namespace Ngs.Collections
{
    // Copyright (c) Microsoft Corporation.  All rights reserved.
    // This source code is made available under the terms of the Microsoft Public License (MS-PL)

    using System;
    using System.Collections.Generic;
    using System.Collections.ObjectModel;
    using System.Linq;
    using System.Reflection;
    using System.Text;

    public static class ReadOnlyExtensions
    {
        internal static ReadOnlyCollection<T> ToReadOnly<T>(this IEnumerable<T> collection)
        {
            ReadOnlyCollection<T> roc = collection as ReadOnlyCollection<T>;
            if (roc == null)
            {
                if (collection == null)
                {
                    roc = EmptyReadOnlyCollection<T>.Empty;
                }
                else
                {
                    roc = new List<T>(collection).AsReadOnly();
                }
            }
            return roc;
        }

        class EmptyReadOnlyCollection<T>
        {
            internal static readonly ReadOnlyCollection<T> Empty = new List<T>().AsReadOnly();
        }
    }
}

   
    
  

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