Two clicks for a button

[Mihail]

Hello !
I try to switch from VB6 to VB.NET.
For now I use 2008 Express Edition.

Look at this code, please:

Public Class frmMovieBuild
    Dim StopMovie As Boolean
 
    Private Sub cmdPlayMovie_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdPlayMovie.Click
        StopMovie = False
        Dim i As Long, jpg As String
        i = 0
        Do While i <= lstMainMovie.Items.Count - 1
                System.Windows.Forms.Application.DoEvents()
            jpg = lstMainMovie.Items.Item(i).ToString
                System.Windows.Forms.Application.DoEvents()
            pic_MoviePreview.Image = Image.FromFile(jpg)
                System.Windows.Forms.Application.DoEvents()
            If StopMovie Then
                MsgBox("Stopped by user")
                Exit Do
            End If
            i = i + StepFrames.Value 'Here I use a slider control
        Loop
    End Sub
 
    Private Sub cmdStopMovie_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdStopMovie.Click
        StopMovie = True
    End Sub
 
End Class
 

When I run the form, first I click the cmdPlayMovie button.
Then I try to exit by clicking the cmdStopMovie button (in order to set the StopMovie variable to TRUE).
And here is the problem:
At the first click, nothing happen. The cmdStopMovie button seems to take the focus.
Then, at the second click, the "Stopped by user" message appear.

For my project is strongly necessary to stop the movie at a certain frame.
That means that cmdStopMovie button must react at the first click.

Is there a bug or there are some settings to do ?

Hope I have explained well my problem.

More one question (If necessary I'll start a new thread for this).
The WHILE clause seems to have no effect in Do-Loop cycle. So this cycle run for ever (except if I click the cmdStopMovie button).
Can someone understand (and explain) WHY ?

Thank you !

[IronRazer]

I have run into the problem you where having in an old program of mine and here is the fix i used for it. I changed a little of the code but it should work fine.

First add a timer. Then use this code :

    Private Sub cmdPlayMovie_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdPlayMovie.Click
        Timer1.Start()
    End Sub
 
    Private Sub cmdStopMovie_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdStopMovie.Click
        StopMovie = True
    End Sub
 
    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        Timer1.Stop()
        StopMovie = False
        Dim i As Long
        i = 0
        While (i <= frames And Not StopMovie)
            System.Windows.Forms.Application.DoEvents()
            jpg = lstMainMovie.Items.Item(i).ToString
            System.Windows.Forms.Application.DoEvents()
            pic_MoviePreview.Image = Image.FromFile(jpg)
            System.Windows.Forms.Application.DoEvents()
            i += StepFrames 'Here I use a slider control
        End While
        If StopMovie Then
            MsgBox("Stopped by user")
        End If
    End Sub