Sorting arrays numerically and alphabetically(like Windows Explorer) without using StrCmpLogicalW or shlwapi.dll - ASP.NET VB

Question

I created a sorter that StrCmpLogicalW / shlwapi.dll. unfortunately it causes errors on partial trust environments. I am in a really bad need of a solution that does not use 'shlwapi.dll' or StrCmpLogicalW and works in the same fashion.

Here's the sorter that causes the error.

Public Class nvSorter
    Implements IComparer(Of String)

    Declare Unicode Function StrCmpLogicalW Lib "shlwapi.dll" ( _
        ByVal s1 As String, _
        ByVal s2 As String) As Int32

    Public Function Compare(ByVal x As String, ByVal y As String) As Integer
        Implements System.Collections.Generic.IComparer(Of String).Compare
        Return StrCmpLogicalW(x, y)
    End Function

End Class

Answer 1

This should work:

Public Class Form1
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim Filenames() As String = New String() {"0", "1", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "2", "20", "3", "4", "5", "6", "7", "8", "9"}
        Array.Sort(Filenames, New CustomComparer)
        MessageBox.Show(String.Join(",", Filenames))
    End Sub
End Class

Public Class CustomComparer
    Implements IComparer(Of String)

    Private Position As Integer
    Private Order As Integer = 1

    Public Sub New(Optional ByVal Ascending As Boolean = True)
        If Not Ascending Then
            Order = -1
        End If
    End Sub

    Private Shared Function EmptyText(ByVal s As String) As Boolean
        Return String.Empty.Equals(s)
    End Function

    Public Function Compare(ByVal x As String, ByVal y As String) As Integer Implements System.Collections.Generic.IComparer(Of String).Compare
        Dim res1 As New List(Of String)(System.Text.RegularExpressions.Regex.Split(x, "(\d+)", System.Text.RegularExpressions.RegexOptions.IgnoreCase))
        Dim res2 As New List(Of String)(System.Text.RegularExpressions.Regex.Split(y, "(\d+)", System.Text.RegularExpressions.RegexOptions.IgnoreCase))
        res1.RemoveAll(AddressOf EmptyText)
        res2.RemoveAll(AddressOf EmptyText)
        Position = 0

        For Each xstr As String In res1
            If res2.Count > Position Then
                If Not IsNumeric(xstr) AndAlso Not IsNumeric(res2(Position)) Then
                    Dim intresult As Integer = String.Compare(xstr, res2(Position), True)
                    If intresult <> 0 Then
                        Return intresult * Order
                    Else
                        Position += 1
                    End If
                ElseIf IsNumeric(xstr) And Not IsNumeric(res2(Position)) Then
                    Return -1 * Order
                ElseIf Not IsNumeric(xstr) And IsNumeric(res2(Position)) Then
                    Return 1 * Order
                ElseIf IsNumeric(xstr) And IsNumeric(res2(Position)) Then
                    Dim res As Integer = Decimal.Compare(Decimal.Parse(xstr), Decimal.Parse(res2(Position)))
                    If res = 0 Then
                        Position += 1
                    Else
                        Return res * Order
                    End If
                End If
            Else
                Return -1 * Order
            End If
        Next

        Return 1 * Order
    End Function
End Class

The result of the above sorting example of "0", "1", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "2", "20", "3", "4", "5", "6", "7", "8", "9" is: