//----------------------------------------------------------------
// Copyright (c) Microsoft Corporation.  All rights reserved.
//----------------------------------------------------------------
namespace System.Activities.Presentation.Internal.PropertyEditing.Model 
{
    using System;
    using System.Collections;
    using System.Collections.Generic;
 
    using System.Activities.Presentation.PropertyEditing;
 
    // <summary>
    // Compares PropertyEntry instances solely on their DisplayName
    // </summary>
    internal class PropertyEntryNameComparer : IComparer, IComparer<PropertyEntry> 
    {
 
        public static readonly PropertyEntryNameComparer Instance = new PropertyEntryNameComparer();
 
        private static int CompareCore(object x, object y) 
        {
            ModelPropertyEntry j = x as ModelPropertyEntry;
            ModelPropertyEntry k = y as ModelPropertyEntry;
 
            if (j == null && k == null) 
            {
                return 0;
            }
            if (j == null) 
            {
                return -1;
            }
            if (k == null) 
            {
                return 1;
            }
 
            return string.Compare(j.DisplayName, k.DisplayName, StringComparison.CurrentCulture);
        }
 
        // IComparer<PropertyEntry> Members
 
        public int Compare(PropertyEntry x, PropertyEntry y) 
        {
            return CompareCore(x, y);
        }
 
 
        // IComparer Members
 
        public int Compare(object x, object y) 
        {
            return CompareCore(x, y);
        }
 
    }
}