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!