Unexpected behaviour inside of nested loops

Question

My Code

    Dim fileReader As StreamReader
    Dim fileName, temp, strVal As String

    For i As Integer = 0 To lbFolder.Items.Count - 1

        Dim iText As String = CStr(lbFolder.Items(i))
        Dim partPath As String = lblPath.Text + "\" + iText
        Dim pathNum As String = partPath + "\2100\"
        Dim directory As New DirectoryInfo(pathNum)
        Dim fileArr As FileInfo() = directory.GetFiles() ' Get a reference to each file in that directory.
        ' Display the names of the files.
        Dim xItem As FileInfo
        For Each xItem In fileArr
            lblFname.Text = xItem.ToString
            strVal = pathNum & xItem.ToString
            lbFiles.Items.Add(strVal)
        Next
        For j = 0 To lbFiles.Items.Count - 1
            fileReader = File.OpenText(pathNum + xItem.ToString)
            temp = fileReader.ReadToEnd
            File.AppendAllText(partPath + "\2100\" + "2100_Merged.txt", temp)
        Next j
        lbFiles.Items.Clear()
    Next i
End Sub

I have a directory with nested folders. With many children and each child having 4 subchilds and each sub child has 4 files.

Parent

...Child

......subchild1

.........File 1

.........File 2

.........File 3

.........File 4

......subchild2

......subchild3

......subchild4

My Intent is to look at each child then bring merge all of the files into one txt file and then move onto the next subchild.

Pseudo Code might look like

open Subchild folder

    for each file in subchild folder 
        listbox.additem(file)
    next

    for each item in listbox
        add to temp file
    next

    output tmp file

next subchild

What is happening is that when going through the

for each xItem in filArr

the next series of iText is occurring which I can see through the watch. This happens even if I have a break at the first next.

How can I correct this?

**Edit*****

For those that might want to test this out here is my entire code.

It requires 2 listboxes, 2 labels , 2 buttons

  Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click

    'open folders
    Dim dialog = New FolderBrowserDialog()
    dialog.SelectedPath = Application.StartupPath
    If DialogResult.OK = dialog.ShowDialog() Then
        lblPath.Text = dialog.SelectedPath
    End If

    For Each folder As String In System.IO.Directory.GetDirectories(lblPath.Text)
        lbFolder.Items.Add(Path.GetFileName(folder))
    Next



End Sub

Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click

    Dim found700 As Boolean
    Dim fileReader As StreamReader
    Dim fileName, temp, strVal As String

    For i As Integer = 0 To lbFolder.Items.Count - 1

        Dim iText As String = CStr(lbFolder.Items(i))
        Dim partPath As String = lblPath.Text + "\" + iText
        Dim pathNum As String = partPath + "\2100\"
        Dim directory As New DirectoryInfo(pathNum)
        Dim fileArr As FileInfo() = directory.GetFiles() ' Get a reference to each file in that directory.
        ' Display the names of the files.
        Dim xItem As FileInfo
        For Each xItem In fileArr
            lblFname.Text = xItem.ToString
            strVal = pathNum & xItem.ToString
            lbFiles.Items.Add(strVal)
        Next
        For j = 0 To lbFiles.Items.Count - 1
            fileReader = File.OpenText(pathNum + xItem.ToString)
            temp = fileReader.ReadToEnd
            File.AppendAllText(pathNum + "2100_Merged.txt", temp)
        Next j
        lbFiles.Items.Clear()
    Next i
End Sub

Answer 1

In your second For loop, change pathNum + xItem.ToString to lbFiles.Items.Item(j)

    For j = 0 To lbFiles.Items.Count - 1
        fileReader = File.OpenText(lbFiles.Items.Item(j))
        temp = fileReader.ReadToEnd
        File.AppendAllText(partPath + "\2100\" + "2100_Merged.txt", temp)
    Next j

Or

    For Each f In lbFiles.Items 
        fileReader = File.OpenText(f)
        temp = fileReader.ReadToEnd
        File.AppendAllText(partPath + "\2100\" + "2100_Merged.txt", temp)
    Next