EntityPropertyComparer.cs :  » Template-Engines » netTiers » PetShop » Business » C# / CSharp Open Source

using System;
using System.Collections;

namespace PetShop.Business{
  /// <summary>
  /// Provide a generic comparer for our entity objects.
  /// </summary>
  public class EntityPropertyComparer : IComparer
  {
    private string PropertyName;

    /// <summary>
    /// Provides Comparison opreations.
    /// </summary>
    /// <param name="propertyName">The property to compare</param>
    public EntityPropertyComparer( string propertyName)
    {
      PropertyName = propertyName;
    }

    /// <summary>
    /// Compares 2 objects by their properties, given on the constructor
    /// </summary>
    /// <param name="x">First value to compare</param>
    /// <param name="y">Second value to compare</param>
    /// <returns></returns>
    public int Compare(object x, object y)
    {
      object a = x.GetType().GetProperty(PropertyName).GetValue(x, null);
      object b = y.GetType().GetProperty(PropertyName).GetValue(y, null);

      if ( a != null && b == null )
        return 1;

      if ( a == null && b != null )
        return -1;

      if ( a == null && b == null )
        return 0;

      return ((IComparable)a).CompareTo(b);
    }
  }
}