list multiple video files duration


I’m working on a project involves movieplayer control for the Raspberry Pi. There is folder named “videos” located at the same folder with executable file, which will store multiple videos for the program to play.
I set up a window and a listbox to show all the legit video files under that folder with file names, duration, etc.
I searched and read the post,
So I set up a timer, in the action() event, the codes are

Listbox_VideoList.Cell(Listbox_VideoList.LastIndex, 1) = MoviePlayer1.Duration.ToText

timer period is 250ms, default mode is off.

In the window contains the listbox control, the open() event codes are

For n As Integer = 0 to App.Videos.Ubound  //App.Videos() is an array stores every legit video files under the folder
    Listbox_VideoList.AddRow(App.videoFileNames(n))   // App.videoFileNames() is an array stores video files names.
    MoviePlayer1.Movie = App.Videos(n)
    Timer_MovieDuration.Mode = Timer.ModeSingle
    'Listbox_VideoList.Cell(Listbox_VideoList.LastIndex, 1) = mDuration
    'Listbox_VideoList.Cell(Listbox_VideoList.LastIndex, 1) = moviePlayer1.Duration.ToText
    Listbox_VideoList.Cell(Listbox_VideoList.LastIndex, 2) = App.videoFileNames(n).NthField(".", 2)
Next n

I currently put two video samples under the folder, named 1.mp4 and 2.mpeg. The code above only lists out the second file’s duration info. Can anyone help? Thanks!