Need "For Each" to read files in numerical order.

Question

My program reads a collection of numbered png images (eg: icon00.png…icon199.png) using a "For…Each" loop and displays them in a ListView box.

Problem: After "Icon10.png", it reads "Icon100.png", "Icon101.png"… assumedly in alphabetical order. :( I need it to read "11" after "10", and "100" after "99".

            intCnt = 1  
            For Each ClosetFile As String In IO.Directory.GetFiles(strClosetPath, strCategory & "*.png", SortOrder.Ascending)  '  "ClosetFile" reads "icon100" after "icon10".  
                Dim img = Image.FromFile(ClosetFile)  
                ImageList2.Images.Add((intCnt - 1).ToString, img)  
                img.Dispose()  
                strRawName = strIconname   
                lsvCollection.Items.Add(ParseItemName(strRawName), (intCnt - 1).ToString)  
                intCnt += 1  
            Next  
            intTotalNumberOfFiles = intCnt - 1  
  

Is there a way to force "For… Each" to read files in numerical order instead of (apparently) alphabetical, or do I have to just read them all and sort them ex post facto? (Note: renumbering user's files is not an option.) :(

TIA

Answer 1

Hi
I am not aware of any inbuit method other than using a SortedDictionary. Here is an example. I used a Function which helps if you need to reuse at other places. To prove the sort, you can manually reorder the testnames to mix them up differently.

Public Class Form1  
  ' this to simulate file naames from  
  ' HDD. Manually mixed up to prove  
  ' the sort.  
  Dim testnames() As String = {"icon101", "icon2", "icon99", "icon10", "icon1", "icon11", "icon100", "icon1000"}  
  Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load  
    With ListBox1  
      .DataSource = New BindingSource(GetFls, Nothing)  
      .DisplayMember = "value"  
    End With  
  End Sub  
  Function GetFls() As SortedDictionary(Of Integer, String)  
    Dim dic As New SortedDictionary(Of Integer, String)  
  
    ' You would read the names as  
    ' usual into a string array  
    ' sorting unecessary.  
  
    ' Dim testnames() As String = IO.Directory.GetFiles(strClosetPath, "*.png")  
  
    For Each s As String In testnames  
      dic.Add(CInt(s.Replace("icon", Nothing)), s)  
    Next  
    Return dic  
  End Function  
End Class  

Answer 2

Thanks for the reply. I'll take a closer look at this in the morning.

I thought I may have come up with a solution on my own but it didn't work. Since I can only add items to an ImageList sequentially, I tried creating an array of images, extracting the position from the filename, inserting them into the array at the proper position, and once complete, copying the sorted array to my "ImageList2".

Everything but this last step works:

        Dim imgImageArray(200) As Image ' Can only add images to ImageList sequentially, so we need an array to add them as read/randomly, added to list in order.  
        ...  
        For intCnt = 1 To intTotalNumberOfFiles             ' Load image array with sorted list.  
            ImageList2.Images.Add(imgImageArray(intCnt))  
        Next  

When I try to copy "imgImageArray(x)" to ImageList, I get an "Invalid Parameter" error. No idea why.

I'll try your method in the morning. Thx.

Answer 3

Hi
OK, for the ImageList I added some code and editted accordingly. Once the SortedDictionary has been filled, a call to GetImages returns the images in the correct order (untested as I don't happen to have a folder of IconXXX.png handy), but the principle should work.

Public Class Form1  
  ' this to simulate file naames from  
  ' HDD. Manually mixed up to prove  
  ' the sort.  
  Dim testnames() As String = {"icon101", "icon2", "icon99", "icon10", "icon1", "icon11", "icon100", "icon1000"}  
  Dim Dic As New SortedDictionary(Of Integer, String)  
  Dim imagelist2 As New ImageList  
  Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load  
    Dic = GetFls()  
    With ListBox1  
      .DataSource = New BindingSource(Dic, Nothing)  
      .DisplayMember = "value"  
    End With  
    imagelist2 = GetImages()  
  End Sub  
  Function GetFls() As SortedDictionary(Of Integer, String)  
    Dim dic As New SortedDictionary(Of Integer, String)  
  
    ' You would read the names as  
    ' usual into a string array  
    ' sorting unecessary.  
  
    ' Dim testnames() As String = IO.Directory.GetFiles(strClosetPath, "*.png")  
  
    For Each s As String In testnames  
      dic.Add(CInt(s.Replace("icon", Nothing)), s)  
    Next  
    Return dic  
  End Function  
  Function GetImages() As ImageList  
    Dim img As New ImageList  
    For Each kvp As KeyValuePair(Of Integer, String) In Dic  
      img.Images.Add(kvp.Key, Image.FromFile(kvp.Value & ".png"))  
    Next  
    Return img  
  End Function  
End Class