Visual Basic rename a group of files - vb.net

Question

I'm starting with Visual Basic and use Visual Studio 2012 and trying to make a tool for renaming a group of files.
How it shoul be:
1- With the "Select Files" button, I can choose the files and they are listed in the ListBox
2- "Old value" is a textbox and is the value to be changed in the filename. For example: fff
3- "New value" is a textbox and is the new value that should replace the old. For example: zzz
4- Rename is a button to start the process.
To rename only one file it's not a problem.
But how to rename all the files from the ListBox which are containing the Oldvalue ?
Can you please help me!
Thanks

Answer 1

I suggest looping over the selected files in the listbox, checking to see which ones contain the OldValue string.
You could use string.contains http://msdn.microsoft.com/en-us/library/dy85x1sa(v=vs.110).aspx?cs-save-lang=1&cs-lang=vb#code-snippet-1
Sounds like you have the replace function sorted since you say it's no problem to do just one file.

Answer 2

Thank you 70Mike.
But I have some problem with the loop.
If it works only for 1 file and not for all.
Here is my code:
Public Class frmRename
Private Sub cmdSelectFile_Click(sender As Object, e As EventArgs) Handles cmdSelectFile.Click
If (OpenFileDialog1.ShowDialog = Windows.Forms.DialogResult.OK) Then
For Each S As String In OpenFileDialog1.FileNames
lstSelectFiles.Items.Add(S)
Next
Else : Exit Sub
End If
End Sub
Private Sub cmdRename_Click(sender As Object, e As EventArgs) Handles cmdRename.Click
Try
For LC As Integer = 0 To lstSelectFiles.Items.Count - 1
Dim s1 As String = lstSelectFiles.Items(LC)
Dim s2 As String = txtbOld.Text
Dim b As String
b = s1.Contains(s2)
Console.WriteLine("Is the string, s2, in the string, s1?: {0}", b)
Do While b = True
Dim oldFile As String = lstSelectFiles.Items(LC)
Dim newFile As String = Replace(lstSelectFiles.Items(LC), txtbOld.Text, txtbNew.Text)
If File.Exists(oldFile) And Not File.Exists(newFile) Then
File.Move(oldFile, newFile)
Kill(oldFile)
End If
Loop
Next
Catch ex As Exception
MsgBox("No file renamed")
End Try
End Sub
End Class