vb.net threading sub slower than call sub

Question

I know this Question was already posted, but it was never really answered, or I did not understand the answer :)

My Problem is that when I call this Sub within the Thread, it takes about 4 sec to execute the code, but if I make a simple Call Sub (Like commented in Code) it takes about 450 ms.

I have a simple program with 2 Subs:

To report Progress on Main Form

To do some "For" Looping

Imports System.Data.SqlClient

Public Class Form1
Public Delegate Sub ProzentDelegate(ByVal Prozent As Double)

Dim G_I_Temp As Integer = 0
Dim G_S_Prüfziffer As String
Dim G_S_Präfix As String
Dim G_I_Zähler As Integer
Dim G_I_Stellen As Integer
Dim G_D_Step As Integer = 1
Dim G_I_Position As Integer
Dim DT_G_Prüftabelle As DataTable
Dim DR_G_Prüftabelle As DataRow
Dim thisLock As New Object
Dim conn As String = "Data Source=SR-SQLWVS;Initial Catalog=Barcode;Integrated Security=True"
Dim sourceconn As New SqlConnection(conn)
Dim adap As SqlDataAdapter
Dim cmd As SqlCommand = New SqlCommand("SELECT TOP(10) * FROM dbo.Prüf_Tabelle", sourceconn)

Dim Thrd_preview As Threading.Thread


Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    sourceconn.Open()

    cmd.Connection = sourceconn
End Sub

Public Sub ReportProgress(ByVal Prozent As Double)
    ProgressBar1.Value = Prozent
End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    If RB_Thread.Checked Then

        If Thrd_preview IsNot Nothing Then Thrd_preview = Nothing
        Thrd_preview = New Threading.Thread(AddressOf DoSomeWork)
        Thrd_preview.IsBackground = True
        Thrd_preview.Start()

    Else
        DoSomeWork()
    End If
End Sub

Private Sub DoSomeWork()


    Dim ds As New DataSet
    DT_G_Prüftabelle = ds.Tables.Add("Prüf_Tabelle")

    Dim L_I_Counter, L_I_Counter2 As Integer
    Dim L_I_Ende As Integer
    Dim L_I_Step As Integer
    Dim L_I_Nutzen As Integer = 1
    L_I_Step = 1
    L_I_Ende = Val(TB_Auftrag_neu_Anzahl.Text)
    G_I_Stellen = 8
    G_S_Prüfziffer = "1"
    G_S_Präfix = "00"
    If TB_Info_Increment.Text = "" Then TB_Info_Increment.Text = 1




adap = New SqlDataAdapter("SELECT TOP(10) * FROM dbo.Prüf_Tabelle", sourceconn)

    adap.FillSchema(DT_G_Prüftabelle, SchemaType.Mapped)

    DT_G_Prüftabelle.Rows.Clear()

    Dim pre As Date = Now

    For L_I_Counter = 1 To (L_I_Ende * L_I_Step) Step L_I_Step
        For L_I_Counter2 = 1 To L_I_Nutzen
            DR_G_Prüftabelle = DT_G_Prüftabelle.NewRow
            DR_G_Prüftabelle.Item("Auftrag_Lfd_nr") = TB_KeyLot.Text
            DR_G_Prüftabelle.Item("Position") = G_I_Position
            G_I_Position += G_D_Step
            DR_G_Prüftabelle.Item("Barcode_soll") = F_Berechnung((Trim(Str(Val(TB_Auftrag_neu_Von.Text) + L_I_Counter - 1))).PadLeft(G_I_Stellen, "0"))
            DT_G_Prüftabelle.Rows.Add(DR_G_Prüftabelle)

        If ProgressBar1.InvokeRequired Then
            ProgressBar1.BeginInvoke(New ProzentDelegate(AddressOf ReportProgress), (L_I_Counter * 100) / (L_I_Ende * L_I_Step))
        Else
            ReportProgress((L_I_Counter * 100) / (L_I_Ende * L_I_Step))
        End If

        Next



    Next


    MsgBox(Now.Subtract(pre).TotalMilliseconds.ToString & " ms.")


End Sub


Function F_Berechnung(ByVal L_Nummer As String) As String
    Dim L_B_Gerade As Boolean = False
    Dim L_I_Prüfziffer As Integer
    Dim L_I_Stellen As Integer
    Me.G_I_Temp = 0

Select Case G_S_Prüfziffer
    Case "0"
        F_Berechnung = L_Nummer
    Case "1"
        F_Berechnung = G_S_Präfix & Trim(L_Nummer)
    Case "2"
        F_Berechnung = G_S_Präfix & Trim(L_Nummer)
    Case "3"
        F_Berechnung = L_Nummer
        '
    Case "5"    '-----Mod 10 gewichtung 31...-----
        L_Nummer = G_S_Präfix & Trim(L_Nummer)
        L_I_Stellen = Len(L_Nummer)
        For Me.G_I_Zähler = L_I_Stellen To 1 Step -1
            Me.G_I_Temp += Val(Mid(L_Nummer, Me.G_I_Zähler, 1)) * IIf(L_B_Gerade, 1, 3)
            L_B_Gerade = Not L_B_Gerade
        Next
        L_I_Prüfziffer = IIf(10 - Me.G_I_Temp Mod 10 = 10, 0, 10 - Me.G_I_Temp Mod 10)
        F_Berechnung = Trim(L_Nummer) & Trim(Str(L_I_Prüfziffer))
        '
    Case "6"    '-----Mod 10 gewichtung 13...-----
        L_Nummer = G_S_Präfix & Trim(L_Nummer)
        L_I_Stellen = Len(L_Nummer)
        For Me.G_I_Zähler = L_I_Stellen To 1 Step -1
            Me.G_I_Temp += Val(Mid(L_Nummer, Me.G_I_Zähler, 1)) * IIf(L_B_Gerade, 3, 1)
            L_B_Gerade = Not L_B_Gerade
        Next
        L_I_Prüfziffer = IIf(10 - Me.G_I_Temp Mod 10 = 10, 0, 10 - Me.G_I_Temp Mod 10)
        F_Berechnung = Trim(L_Nummer) & Trim(Str(L_I_Prüfziffer))
        '


    Case Else
        F_Berechnung = L_Nummer

End Select

End Function

I have tried to take out Progress Reporting but the Result is the same.

I hope you have some suggestions or solutions for me. I would be very thankful.

Edo Spahić · Accepted Answer

Just wanted to report that I found a solution.

The main problem was this line of code in:

DR_G_Prüftabelle.Item("Auftrag_Lfd_nr") = TB_KeyLot.Text

So if I start this Sub from another Thread rather than from a Main Thread, for every single loop it has to go to main thread and to take Paramater from TextBox and to go back in Thread to Loop further.

I took that out, declared a variable at the begining and assigned this TextBox value to it and it works like charm.

Also I took a suggestion from dbasnett to Invoke Reporting every time without If-Else and also the suggestion from Steven Doggart to Report every 100 Loops.

You guys helped a lot. Thanks for that!!

vb.net threading sub slower than call sub

Answers (2)

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