Tim Van Wassenhove

The journey of a thousand miles begins with one step.

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IComparer comparer = Comparer<t>.Default;
itemsList.Sort(delegate(T t1, T t2)
{
 object property1 = prop.GetValue(t1);
 object property2 = prop.GetValue(t2);
 return reverse * comparer.Compare(property1, property2);
});

Type comparablePropertyType = typeof(Comparer<>).MakeGenericType(property.PropertyType);
IComparer comparer = (IComparer)comparablePropertyType.InvokeMember("Default", BindingFlags.Static | BindingFlags.GetProperty | BindingFlags.Public, null, null, null);

Type propertyType = property.PropertyType;

// this cache minimizes the cost of reflection in the PropertyComparer constructor
PropertyComparer<t> comparer;
if (!this.comparers.TryGetValue(propertyType, out comparer))
{
 comparer = new PropertyComparer<t>(property, direction);
 this.comparers.Add(propertyType, comparer);
}
else
{
 comparer.SetListSortDirection(direction);
}

itemsList.Sort(comparer);

PropertyDescriptor GetPropertyDescriptor(object component, string propertyName)
{
 PropertyDescriptorCollection propertyDescriptors = TypeDescriptor.GetProperties(component);
 foreach (PropertyDescriptor propertyDescriptor in propertyDescriptors)
 {
  if (propertyDescriptor.Name == propertyName)
  {
   return propertyDescriptor;
  }
 }

 throw new ArgumentException(string.Format("The property '{0}' was not found.", propertyName));
}

1. Scott Ballard September 29, 2008 at 23:58

   Hi Tim,

   First, let me thank you for providing this source code. It really helped me quickly develop a concrete class for the IBindingList interface that supports sorting. I did have one small piece of feedback though. My business objects have several string properties. If I use your source code as is, the first string property I sort on works fine. However, if I try to sort on a second string property, it uses the sorting from the first string property. I think this is because the PropertyComparer you store for each property type is tied to the first property that was used for sorting. I think your PropertyComparer class needs a new method as follows:

   public void SetPropertyDescriptor(PropertyDescriptor property)
   {
   this.propertyDescriptor = property;

   }

   Then, the ApplySortCore method in your SortableBindingList class needs a new line as follows:

   comparer.SetPropertyDescriptor(property);

   This would go right before:

   comparer.SetListSortDirection(direction);

   So not only does the new sort direction get updated, but the new property to sort on gets updated too. That seemed to fix the problem for me. I hope this all makes sense. You can see the behavior I’m describing if you take your demo app and add first and last name string properties to your Person class. If you sort on last name first, it works fine. But then if you sort on first name, it still uses the sorting from the last name. Again, nice work, I just wanted to offer a slight improvement.

   Regards,

   Scott Ballard
   sd_ballard@hotmail.com
2. timvw September 30, 2008 at 09:20

   Hello Scott,

   Thanks for the feedback, it allowed me to reproduce the problem quickly.

   It took me a bit more to write a failing unittest that reproduced the behaviour because there was a bug in my unittests :/

   Anyway, the problem has been solved now and the code has been committed into the BeTimvwFramework repository. I have uploaded a fixed demo application.
3. Andy B January 31, 2009 at 08:55

   This works a treat. Fantastic code Tim!
4. Paul Hodgson April 6, 2009 at 22:59

   Very nice saved me a bit of grief and given how simple it is I can’t see why the doesn’t DGV include this functionality? ho-hum.

   VB is my native language and ran the BindingList and comparer source through a c#-to-vb translator and it pretty much worked straight out of the box. Just have to look for

   Public Function Compare(ByVal x As T, ByVal y As T) As Integer and be certain it implements System.Collections.Generic.IComparer(Of T).Compare.

   Thanks again.

   Paul
5. Alex Birch April 8, 2009 at 22:17

   Thank you for not only doing this but sharing.

   Way to go!
6. Mathieu Daigle May 21, 2009 at 16:19

   Works like a charm.

   Good job and thanks for sharing your knowledge.
7. Yvan Rodrigues May 25, 2009 at 02:08

   Very nice work!
8. Ramiro June 2, 2009 at 19:23

   Perfect! a good solution for an incomplete topic of .NET.

   Gracias por todo. Saludos
9. Tom Bushell December 29, 2009 at 21:10

   Nice job – I just dropped 2 files into my project, and it “just worked”!

   The only tweak I’ve done so far is to put the PropertyComparer class in the same file as the SortableBindingList – I like having a single file solution that can be shared with other projects.

   -Tom
10. Robin Clark February 19, 2010 at 18:27

    Wow – I have to confess that as I was mucking about with IQueryable results from Entity Framework queries I would have a lot of problems, but just converting the IQueryable to a list and wrapping it in the sortablelist worked immediately!
11. Paul Peavyhouse March 23, 2010 at 21:42

    Excellent!
    Two questions:
    1) Is there an obviously simple & efficient way to make the sort not mutate the original list? I want add/inserts to list to remain immutable; I just want them to *display* in different order according to the chosen sorting column.
    2) Do you think this would easily work on VirtualMode=true DGVs?

    Danka!

    Pv
12. Mikael Fredriksson October 19, 2010 at 13:30

    Many thanks! Works perfectly.
13. Haw-Bin Chai January 16, 2011 at 17:54

    Fantastic – thanks for this!!
14. Rajesh February 25, 2011 at 07:29

    HI Tim,
    it was a great solution, it helped me very much in enabling sorting for DataGridView. ThankYou very much.
15. Uwe March 28, 2011 at 02:39

    Unfortunately, it does not support filtering. How to implement that? Help would be appreciated
16. Alex Terra June 10, 2011 at 21:19

    Genius your are my friend!!!

    Congrats from Brazil!
17. Koby July 12, 2011 at 16:30

    I’ve spent a few hours today on the web trying to figure how to enable the sort of the DataGridView.
    finally I have found this great article.
    Thanks for sharing!
    it really works great!
18. kra July 25, 2011 at 10:26

    It helped me a lot, thanks

    cheers
19. Marcel October 25, 2011 at 14:53

    Congratulations for this nice class.
    I have though a question:
    How can I use this when working with Entity Framework:

    public partial class FrmEF : Form
    {
    private academieEntities acaEnt;

    private void FrmEF_Load(object sender, EventArgs e)
    {
    myDataGridView.DataSource = myBindingSource;
    aca = new academieEntities();

    myBindingSource.DataSource = aca.acaEnt;

    }
    }
    My Gridview is populate but I don’t know how to use your class to make its column sortable.

    Thanks
20. Cris McL November 1, 2011 at 19:53

    @Marcel you can do it like this:

    aca = new academiEntities();
    var academi = from a in aca.TableName select a;
    myBindingSource.DataSource = new SortableBindingList(academi.AsEnumerable());
21. Andrew January 20, 2012 at 05:35

    Thanks for the great work!
22. Jakub February 3, 2012 at 21:30

    This is it, thank you!
23. Dan J March 15, 2012 at 11:26

    Tim, this is great. Thank you for doing it, and thank you for releasing it.
24. Ronzul March 17, 2012 at 14:25

    Many thanks for this!
25. Dave Nicolas April 11, 2012 at 17:07

    Thanks for the excellent work!
26. Dovlet Mamenov May 10, 2012 at 10:44

    Hi Tim,

    Thank you for your source code,

    my question:
    Is it possible to add a second parameter for sort operation in your SortableBindingList

    for example I have a SortableBindingList of Person class which has properties: Name (string) Surname (string) DateOfBirth (DateTime) and PersonID which is Integer. When I press to Name column header of dagatagridview which is bound to my SortableBindingList can I have my Persons to be sorted by Name + by PersonID (if names are equal then use PersonID for comparison).

    Will be very glad for your detailed answer!

    Thank you for your time!
27. Artiom K. May 13, 2012 at 16:07

    Hi Tim. Thank you very much for this solution. It’s really great when it is very easy to apply solution just in a few clicks. Thanks a lot!!!

    By the way, I needed to use sorting, but to keep the last row in the fixed position (to be always the last row).
    May be it will be useful for somebody. Happy codding.
    
public class FixedLastRowSortedList : SortableBindingList {
public FixedLastRowSortedList() {}

    public FixedLastRowSortedList(IEnumerable enumeration) : base(enumeration) {}

    protected override void ApplySortCore(PropertyDescriptor property, ListSortDirection direction) {
    var lastRow = Items.LastOrDefault();
    var itemsList = (List)GetListButLastRow();

    var propertyType = property.PropertyType;
    var comparer = GetOrCreateComparer(property, direction, propertyType);

    comparer.SetPropertyAndDirection(property, direction);
    itemsList.Sort(comparer);
    if(!Equals(lastRow, default(T)))
    itemsList.Add(lastRow);

    Items.Clear();
    foreach (var item in itemsList) {
    Items.Add(item);
    }

    PropertyDescriptor = property;
    ListSortDirection = direction;
    isSorted = true;

    OnListChanged(new ListChangedEventArgs(ListChangedType.Reset, -1));
    }

    private IList GetListButLastRow() {
return Items.Count > 1 ? Items.ToList().GetRange(0, Items.Count - 1) : Items;
}
}