Sort Method for an ASP.NET DropDownList

Introduction

I recently found a requirement in my ASP.NET application that needed to be able to sort a DropDownList control. Oddly enough I couldn't find a sort method within the framework, so I made my own. The code below shows what I did as a quick option, but you can of course use similar code to create a custom control that inherits from the DropDownList control.

Code

Private Sub SortDropDown(ByVal dd As DropDownList)
    Dim ar As ListItem()
    Dim i As Long = 0
    For Each li As ListItem In dd.Items
        ReDim Preserve ar(i)
        ar(i) = li
        i += 1
    Next
    Dim ar1 As Array = ar

    ar1.Sort(ar1, New ListItemComparer)
    dd.Items.Clear()
    dd.Items.AddRange(ar1)
End Sub
Private Class ListItemComparer _
    Implements IComparer

    Public Function Compare(ByVal x As Object, _
          ByVal y As Object) As Integer _
          Implements System.Collections.IComparer.Compare
        Dim a As ListItem = x
        Dim b As ListItem = y
        Dim c As New CaseInsensitiveComparer
        Return c.Compare(a.Text, b.Text)
    End Function
End Class

Summary

As I mentioned, this can easily be put into a custom control by simply creating a new class. Inherit from the DropDownList control and add the above code to the class. That's all. When you create your ASP.NET web form, you can drag and drop a normal DropDownList to your form, and edit the declaration in your code behind form, to use your custom class. Enjoy!