[RESOLVED] Read files, get highest numeric value from file name.

[sRLS]

I have a list box populated with file names from a folder, each file name ends with a "_A1" Underscore, Alpha character and a numeric value, the Alpha and Numeric values vary. The Numeric value can vary in length.
Example File names:
6081058_E_2020_Part 1 of 2_A99.zmp
6081058_E_2020_Part 1 of 2_D12.zmp
I'm able to extract the numeric value in the code below, where I am struggling is how to write code to select the highest numeric value without user interaction and place that value in a text box.

    Private Sub ListBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ListBox1.SelectedIndexChanged
        sLastNumber = ListBox1.Text
        LastNumber.Text = sLastNumber.Substring(sLastNumber.LastIndexOf("_") + 1)
        NextNo.Text = Replace(LastNumber.Text, "D", "") + 1
    End Sub

This is the code to populate my list box.

    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        'Set up sMyPath string and variables
        sJobNumber = JobNumber.Text
        sOpNumber = OpNumber.Text
        sPartX1 = PartX1.Text
        sPartX2 = PartX2.Text
        sMyPath = "\\ACCURATENAS\CMM_Vault\CMM - Inspection Results & Zeiss Table Files_Vault\CMM-Inspection-Measuring-Points\" & sJobNumber & "\" & sOpNumber & "\" & "Part " & sPartX1 & " of " & sPartX2 & "\"
        sMsgPath = sJobNumber & "\" & sOpNumber & "\" & "Part " & sPartX1 & " of " & sPartX2
        ListBox1.Items.Clear()

        'Check if path exists
        If CheckPathParts(sMyPath) Then
            'MessageBox.Show("The path exists!")
            Try
                Dim pathToCheck As String = sMyPath
                If My.Computer.FileSystem.GetFiles(pathToCheck).Count Then
                    For Each file As String In My.Computer.FileSystem.GetFiles(pathToCheck)
                        ListBox1.Items.Add(IO.Path.GetFileNameWithoutExtension(file))
                    Next
                End If
                'End If
            Catch ex As Exception ' this section of code doesnt appear to function or catch errors.
                MsgBox("Message: " & ex.Message & vbNewLine & "StackTrace: " & ex.StackTrace, MsgBoxStyle.Critical, "Error...")
            End Try
        Else
            'MsgBox(sSubDirFailed)
            MsgBox("There are no files in: " & sMsgPath & ": Or the path doesn't exist: " & sSubDirFailed & ". Check to ensure entered data is correct.")
        End If
    End Sub

Any help, examples or reading materials for a new VB user is appreciated.

[si_the_geek]

Your use of Substring gets everything after the last _ so you end up with something like "A99.zmp"

If you want to extract just the numeric value then you need to start one character later (so change +1 to +2), and only take a particular amount of characters, eg:

LastNumber.Text = sLastNumber.Substring(sLastNumber.LastIndexOf("_") + 2, 2)

The Numeric value can vary in length.

In order to determine how many characters you want, find the last "_" character and the last "." character, and subtract one from the other.

[4x2y]

The following code extract Alpha character and Numeric value whatever its length

Private Sub ListBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ListBox1.SelectedIndexChanged
        Dim strFileName As String = IO.Path.GetFileNameWithoutExtension(ListBox1.SelectedItem.ToString)
        Dim i As Integer = strFileName.LastIndexOf("_"c)
 
        TextBox1.Text = strFileName.Substring(i + 1, 1) ' Alpha character
        TextBox2.Text = strFileName.Substring(i + 2) + 1 ' Next numeric value
    End Sub

[sRLS]

The following code extract Alpha character and Numeric value whatever its length

Private Sub ListBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ListBox1.SelectedIndexChanged
        Dim strFileName As String = IO.Path.GetFileNameWithoutExtension(ListBox1.SelectedItem.ToString)
        Dim i As Integer = strFileName.LastIndexOf("_"c)
 
        TextBox1.Text = strFileName.Substring(i + 1, 1) ' Alpha character
        TextBox2.Text = strFileName.Substring(i + 2) + 1 ' Next numeric value
    End Sub

Amazing!
Your 5 lines of code replaces my 15 line attempt.

[sRLS]

si_the_geek and 4x2y
Thank you for your time!