Im trying to make a little program that list all folders/subfolders in a directory that I specify in a TextBox, and I also want the program to show a messagebox If i write something wrong in the textbox like folders that not exits etc. but I cant get this to work.

This is my code so far:

Public Class Form1

    Private Sub btnListFolder_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnVisInnhold.Click
        'Create variabel
        Dim strFolder As String
        Dim strFolderName As String

        'Textbox for writing folder/station name
        strFolderName = TextBox1.Text

        'list all folders
        For Each strFolder In _
        My.Computer.FileSystem.GetDirectories(strFolderNam e)

            If My.Computer.FileSystem.DirectoryExists(strFolder) Then

                'Add the item to the list
                ListBox1.Items.Add(strFolder)

                'Tell the user
                MessageBox.Show("Found it, exiting the loop now.", "Info")
                'Quit the loop early

            Else
                MessageBox.Show("Folder/station does not exists.", "Error")

                Exit For

            End If

        Next

    End Sub