Looping through Playlist - vb.net

Question

I am having trouble looping through my playlist of mp3 tracks.
Can anybody shed some light on where I am going wrong. This is the code. It play the first track, but then stops.
Code has been edited 011020
' The following Menu Item plays the full list of mp3s in the list box
Private Sub PlayListToolStripMenuItem_Click(sender As Object, e As EventArgs)
Handles PlayListToolStripMenuItem.Click
FromDictionary = False
PlaySongsFromListBox()
End Sub
Private Sub PlaySongsFromListBox()
'MsgBox("Index Counter = " & NextIndex)
'MsgBox("Total No of Tracks = " & ListBox1.Items.Count)
If NextIndex = ListBox1.Items.Count Then
NextIndex = 0
MessageBox.Show("All music has been played")
Exit Sub
End If
Dim item As KeyValuePair(Of String, String) =
DirectCast(ListBox1.Items(NextIndex), KeyValuePair(Of String, String))
Dim SongPath = Path.Combine(item.Value, item.Key)
PlayASong(SongPath)
End Sub
Private Sub PlayASong(SongPath As String)
MsgBox("Playing Track: " & SongPath)
CurrentMediaStreamName = SongPath
MediaPlayer1.URL = SongPath
MediaPlayer1.Ctlcontrols.play()
MsgBox("Playing Track: " & SongPath)
End Sub
Private Sub MediaPlayer1_PlayStateChange(sender As Object, e As
AxWMPLib._WMPOCXEvents_PlayStateChangeEvent) Handles
MediaPlayer1.PlayStateChange
If MediaPlayer1.playState = WMPLib.WMPPlayState.wmppsMediaEnded Then
NextIndex += 1
PlaySongsFromListBox()
End If
End Sub

Answer 1

At the class level (Form1) I declared 4 variables that are used in more than one method.
In the Form.Load I filled the MusicDictionary. You may be filling this from a database or text file. I also bound the ListBox to the dictionary. The ListBox.DataSource cannot take a Dictionary directly but a BindingSource can handle it.
PlayASong simply does what it says.
PlaySongsFromDictionary first checks if we have come to the end of the Dictionary. Note that I reset NextIndex back to 0. I used Path.Combine to get the path for the song. Notice that in one dictionary entry, I left out a back slash at the end of the directories and in the other entry I included the backslash. Path.Combine accepted both and added a back slash where necessary. Also notice that the index is applied to the Keys collection and the Values collection of the Dictionary not the Dictionary itself. If we tried to apply the index to the dictionary it would be trying to look for the Key inside the brackets. Default Public Property Item(key As TKey) As TValue
PlaySongsFromListBox casts the list box item (which is an object) back to its underlying type, KeyValuePair.
Finally, the important part! I used the MediaEnded event of the MediaPlayer1 to determine when to play the next song. Here I incremented the index and called the one of the PlaySongs... methods.
Private NextIndex As Integer
Private WithEvents MediaPlayer1 As New MediaPlayer
Private MusicDictionary As New Dictionary(Of String, String)
Private FromDictionary As Boolean
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
MusicDictionary.Add("2018-11-27_-_Track_A_-_FesliyanStudios.com_By_Stephen_Bennett.mp3", "C:\Users\maryo\Documents\Marys Music")
MusicDictionary.Add("file_example_MP3_700KB.mp3", "C:\Users\maryo\Documents\Marys Music\")
ListBox1.DataSource = New BindingSource(MusicDictionary, Nothing)
ListBox1.DisplayMember = "Key"
ListBox1.ValueMember = "Value"
End Sub
Private Sub PlayASong(SongPath As String)
MediaPlayer1.Open(New Uri(SongPath))
MediaPlayer1.Play()
End Sub
Private Sub PlaySongsFromDictionary()
If NextIndex = MusicDictionary.Count Then
NextIndex = 0
MessageBox.Show("All music has been played")
Exit Sub
End If
Dim SongPath = Path.Combine(MusicDictionary.Values(NextIndex), MusicDictionary.Keys(NextIndex))
PlayASong(SongPath)
End Sub
Private Sub PlaySongsFromListBox()
If NextIndex = ListBox1.SelectedItems.Count Then
NextIndex = 0
MessageBox.Show("All music has been played")
Exit Sub
End If
Dim item As KeyValuePair(Of String, String) = DirectCast(ListBox1.SelectedItems(NextIndex), KeyValuePair(Of String, String))
Dim SongPath = Path.Combine(item.Value, item.Key)
PlayASong(SongPath)
End Sub
Public Sub MediaPlayers1_MediaEnded() Handles MediaPlayer1.MediaEnded
NextIndex += 1
If FromDictionary Then
PlaySongsFromDictionary()
Else
PlaySongsFromListBox()
End If
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
FromDictionary = False
PlaySongsFromListBox()
End Sub
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
FromDictionary = True
PlaySongsFromDictionary()
End Sub

Answer 2

The problem with the MP3's not looping was solved using the following invoke method
If e.newState = WMPLib.WMPPlayState.wmppsStopped Then
Me.BeginInvoke(New Action(AddressOf NextSong))
End If
Found at the following location Function call only works when MessageBox.Show() is included?