[RESOLVED] How to pass value from form to custom class? Please help

[Peter Porter]

I have a process class that needs a fps integer from the main form. This integer changes between 24 to 30fps. I tried to pass this integer by making it publically shared on form1, but the ffmpeg process wouldn't start because it didn't recieve it. I know this is the problem because when I manually enter this integer to the process class arguments, ffmpeg starts.

Form1:

Public Class Form1


Public shared fps As Single


    Dim proc2 As New VideoProcess


    Private Sub Record_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Record.Click

    fps = 30

    'starts ffmpeg process for captured frames
    proc2.Start()

    End Sub

Process Class:

Public Class VideoProcess


    Inherits Process

    Dim dir As String = Environment.GetFolderPath(Environment.SpecialFolder.MyVideos)
    

    Public Sub New()

    StartInfo.FileName = dir & "\" & "\Captured\ffmpeg.exe"
    StartInfo.Arguments = String.Format("-f image2pipe -r " & Form1.fps & " -i pipe:.bmp -pix_fmt yuv420p -c:v libx264 -crf 18 -g 1 -y -r " & Form1.fps & " " & dir & "\Captured\Temp.mp4")
    StartInfo.UseShellExecute = False
    StartInfo.WindowStyle = ProcessWindowStyle.Hidden
    StartInfo.RedirectStandardInput = True
    StartInfo.RedirectStandardOutput = True
    StartInfo.CreateNoWindow = True

    End Sub


End Class

Niya gave me the idea of adding a custom property to the process class, but that also didn't work. Should've!

Public Class Form1
    Dim proc2 As New VideoProcess
     
    Private Sub Record_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Record.Click
    'starts ffmpeg process for captured frames
    proc2.FPS = 30
    proc2.Start()
    End Sub

End Class

Public Class VideoProcess
    Inherits Process
     
    Dim dir As String = Environment.GetFolderPath(Environment.SpecialFolder.MyVideos)
     
    Public Property FPS As Integer
    Public Sub New()
     
    StartInfo.FileName = dir & "\" & "\Captured\ffmpeg.exe"
    StartInfo.Arguments = String.Format("-f image2pipe -r " & Me.FPS.ToString & " -i pipe:.bmp -pix_fmt yuv420p -c:v libx264 -crf 18 -g 1 -y -r " & Me.FPS.ToString & " " & dir & "\Captured\Temp.mp4")
    StartInfo.UseShellExecute = False
    StartInfo.WindowStyle = ProcessWindowStyle.Hidden
    StartInfo.RedirectStandardInput = True
    StartInfo.RedirectStandardOutput = True
    StartInfo.CreateNoWindow = True
     
    End Sub
     
End Class

How can I pass this integer from the main form to this process class? Please help

[Edgemeal]

Passing it in the constructor is one way,..

Public Class Form1

    Private proc2 As VideoProcess = Nothing
    Private Property fps As Integer

    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        Me.fps = 30
        proc2 = New VideoProcess(Me.fps)
    End Sub

End Class

Public Class VideoProcess

    Public Property FPS As Integer

    Public Sub New(ByVal fps As Integer)
        Me.FPS = fps
        MessageBox.Show(String.Format("Me.FPS = {0}", Me.FPS))
    End Sub

End Class

[Peter Porter]

Edgemeal, thank you!

I made some minor changes. It works like a charm!

Public Class Form1

    Private proc2 As VideoProcess = Nothing
    Private Property fps As Integer

    Private Sub Record_Click(sender As System.Object, e As System.EventArgs) Handles Record.Click
        fps = CInt(Button1.Text) 'this button's text changes from 24 to 30fps
        proc2 = New VideoProcess(fps)
        proc2.Start()
    End Sub

End Class

Public Class VideoProcess

    Inherits Process

    Dim dir As String = Environment.GetFolderPath(Environment.SpecialFolder.MyVideos)

    Public Sub New(ByVal fps As Integer)

        StartInfo.FileName = dir & "\" & "\Captured\ffmpeg.exe"
        StartInfo.Arguments = String.Format("-f image2pipe -r " & fps & " -i pipe:.bmp -pix_fmt yuv420p -c:v libx264 -crf 18 -g 1 -y -r " & fps & " " & dir & "\Captured\Temp.mp4")
        StartInfo.UseShellExecute = False
        StartInfo.WindowStyle = ProcessWindowStyle.Hidden
        StartInfo.RedirectStandardInput = True
        StartInfo.RedirectStandardOutput = True
        StartInfo.CreateNoWindow = True

    End Sub


End Class

[Edgemeal]

& FPS &

If FPS is an Integer then VB will automatically convert it to a string using MS.VB class, I believe .ToString is the preferred .Net way,

& FPS.ToString &

[ident]

tostring does not convert the object. Only gets its string representation.

[ident]

I dont see any need for a new class here. I also notice you are using default instances.

[Peter Porter]

Just trying to better organize my code for my project below.

[Edgemeal]

tostring does not convert the object. Only gets its string representation.

I'm not sure what actually goes on behind the code, but when you use & Integer & the IL code produces legacy code using MS.VB, same code as if you used CStr() instead of .ToString,...

 Dim s As String = (1).ToString

call       instance string [mscorlib]System.Int32::ToString()

---

Dim s As String = CStr(1)

call       string [Microsoft.VisualBasic]Microsoft.VisualBasic.CompilerServices.Conversions::ToString(int32)