Genric List Sorting

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI.WebControls;
using System.Reflection;

///

/// Summary description for GListSorting
///

public static class GListSorting
{
public static void Sort(this List list, string sortExpression)
{
string[] sortExpressions = sortExpression.Split(new string[] { "," }, StringSplitOptions.RemoveEmptyEntries);

List comparers = new List();

foreach (string sortExpress in sortExpressions)
{
string sortProperty = sortExpress.Trim().Split(' ')[0].Trim();
string sortDirection = sortExpress.Trim().Split(' ')[1].Trim();

Type type = typeof(T);
PropertyInfo PropertyInfo = type.GetProperty(sortProperty);
if (PropertyInfo == null)
{
PropertyInfo[] props = type.GetProperties();
foreach (PropertyInfo info in props)
{
if (info.Name.ToString().ToLower() == sortProperty.ToLower())
{
PropertyInfo = info;
break;
}
}
if (PropertyInfo == null)
{
throw new Exception(String.Format("{0} is not a valid property of type: \"{1}\"", sortProperty, type.Name));
}
}

SortDirection SortDirection = SortDirection.Ascending;
if (sortDirection.ToLower() == "asc" || sortDirection.ToLower() == "ascending")
{
SortDirection = SortDirection.Ascending;
}
else if (sortDirection.ToLower() == "desc" || sortDirection.ToLower() == "descending")
{
SortDirection = SortDirection.Descending;
}
else
{
throw new Exception("Valid SortDirections are: asc, ascending, desc and descending");
}

comparers.Add(new GenericComparer { SortDirection = SortDirection, PropertyInfo = PropertyInfo, comparers = comparers });
}
list.Sort(comparers[0].Compare);
}
}

public class GenericComparer
{
public List comparers { get; set; }
int level = 0;

public SortDirection SortDirection { get; set; }
public PropertyInfo PropertyInfo { get; set; }

public int Compare(T t1, T t2)
{
int ret = 0;

if (level >= comparers.Count)
return 0;

object t1Value = comparers[level].PropertyInfo.GetValue(t1, null);
object t2Value = comparers[level].PropertyInfo.GetValue(t2, null);

if (t1 == null || t1Value == null)
{
if (t2 == null || t2Value == null)
{
ret = 0;
}
else
{
ret = -1;
}
}
else
{
if (t2 == null || t2Value == null)
{
ret = 1;
}
else
{
ret = ((IComparable)t1Value).CompareTo(((IComparable)t2Value));
}
}
if (ret == 0)
{
level += 1;
ret = Compare(t1, t2);
level -= 1;
}
else
{
if (comparers[level].SortDirection == SortDirection.Descending)
{
ret *= -1;
}
}
return ret;
}
}
----------------------------

Ex.


List objListPro = category.GetcategoryproductsByEmail(Membership.GetUser(Page.User.Identity.Name).Email.ToString());
objListPro .Sort("ID ascending");

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URL:
http://www.codeproject.com/Articles/27834/Generic-List-Sort-Function