have made a class using Generic that sorts any custom type collection based
on the selected property. When sorting on "PageName" it works fine, but when
sorting on "Index" I get Null Reference Exeption. Hope some smart guru can
help me out !!! :)

public class MyPageData : Dictionary<String, object>
{
   private string pageName;

   public string PageName
   {
       get {
           if (pageName == null)
           {
               pageName = (string)this["PageName"] ?? "";
           }
           return pageName; }
   }

}

protected void Page_Load(object sender, EventArgs e)
{
   List<MyPageData> myPageDataCollection = new List<MyPageData>();

   MyPageData page = new MyPageData();

   page.Add("PageName", "John");
   page.Add("Index", 1);

   myPageDataCollection.Add(page);

   page = new MyPageData();

   page.Add("PageName", "Elizabeth");
   page.Add("Index", 7);

   myPageDataCollection.Add(page);
   page = new MyPageData();

   page.Add("PageName", "Paul");
   page.Add("Index", 10);

   myPageDataCollection.Add(page);

   page = new MyPageData();

   page.Add("PageName", "Andrew");
   page.Add("Index", 4);

   myPageDataCollection.Add(page);

   foreach (MyPageData _page in myPageDataCollection)
   {
       Response.Write(_page.PageName + "<br/>");
   }

   Response.Write("Sorted list?<br/>");

   myPageDataCollection.Sort(new GenericComparer<MyPageData>("PageName",
GenericComparer<MyPageData>.SortOrder.Ascending));

   foreach (MyPageData _page in myPageDataCollection)
   {
       Response.Write(_page.PageName + "<br/>");
   }

}

---------------------------------------------
This Works:
---------------------------------------------
myPageDataCollection.Sort(new GenericComparer<MyPageData>("PageName",
GenericComparer<MyPageData>.SortOrder.Ascending));

---------------------------------------------
This fails: (Null reference exeption)
---------------------------------------------
myPageDataCollection.Sort(new GenericComparer<MyPageData>("Index",
GenericComparer<MyPageData>.SortOrder.Ascending));

/// <summary>
/// This class is used to compare any
/// type(property) of a class for sorting.
/// This class automatically fetches the
/// type of the property and compares.
/// </summary>

public sealed class GenericComparer<T> : IComparer<T>
{
   public enum SortOrder { Ascending, Descending };

   #region member variables
   private string sortColumn;
   private SortOrder sortingOrder;
   #endregion

   #region constructor
   public GenericComparer(string sortColumn, SortOrder sortingOrder)
   {
       this.sortColumn = sortColumn;
       this.sortingOrder = sortingOrder;
   }
   #endregion

   #region public property
   /// <summary>
   /// Column Name(public property of the class) to be sorted.
   /// </summary>
   public string SortColumn
   {
       get { return sortColumn; }
   }

   /// <summary>
   /// Sorting order.
   /// </summary>
   public SortOrder SortingOrder
   {
       get { return sortingOrder; }
   }
   #endregion

   #region public methods
   /// <summary>
   /// Compare interface implementation
   /// </summary>
   /// <param name="x">custom Object</param>
   /// <param name="y">custom Object</param>
   /// <returns>int</returns>

   public int Compare(T x, T y)
   {
       PropertyInfo propertyInfo = typeof(T).GetProperty(sortColumn);
       IComparable obj1 = (IComparable)propertyInfo.GetValue(x, null);
       IComparable obj2 = (IComparable)propertyInfo.GetValue(y, null);

       if (sortingOrder == SortOrder.Ascending)
       {
           return (obj1.CompareTo(obj2));
       }
       else
       {
           return (obj2.CompareTo(obj1));
       }
   }

   #endregion

}