asked on 5/14/2011

cancel backgroundworker from a separate form

Hi Experts,

i'm very new at VB and here is my dilema, i have form A that calls a backgroundwoeker to run a very long process. once the user clicks on submit on form A it calls the BGworker and opens form B.

on form B load i'm closing form A - form B has a progress bar, a cancel button and other info i display to the user what i'm stuck is with the cancel button - how can i have form B send a cancelationrequest to the backgroundworker.

Also if not too much to ask - how can i catch progresschangeevents and workercompleted events in form B

Many thanks in advance.

Visual Basic.NET .NET Programming Visual Basic Classic

Last Comment

starlite551

5/15/2011

Nasir Razzaq

5/14/2011

Where is the backgroundworker? Is it on FormA or on a separate class? You can pass the reference of backgroundworker from FormA to FormB(using a class level variable in FormB) and then use it to cancel. To catch the events, you would need to use AddHandler statement.

Why not add the backgroundworker on FormB?

hrodriguez761

5/14/2011

ASKER

Hi CodeCruiser,

The BGworker is on a dll i created with the entire long process - i'm passing some data from FORM A to it - that's why im calling it from there - FORM B has the progress bar and other indicators i want the user to see while the BGWorker is doing it's thing.

Thanks,

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Nasir Razzaq

5/14/2011

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starlite551

5/14/2011

Send the object of BackGroundWorker Class as a parameter to a parameterized constructor of Form B. Then in a button click from Form B. Call the CancelAsync() Method of BackGroundWorker object. Like so Suppose name of the object is bgWorker :

bgWorker.CancelAsync();

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starlite551

5/14/2011

Constructor of Form B will be as follows :

Dim BackGroundWorker bgWorker
Public FormB(BackGroundWorker worker)
Begin
Me.bgWorker = worker
End

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hrodriguez761

5/14/2011

ASKER

Sorry guys,

i have been trying to get this to work for the past hour with no luck. and I made a mist when i was writing my explanation above. the backgroundwork is being called from FORM A - and sending all the process contained in the dll to it. I'm not sure if this changes things.

@codecruiser - I guess i could do option 1 if everything else fails

@ starlite551 - I did not understood how to implement the constructor on form b - i have attached my current code on FORM B

Thanks you both

Imports System.ComponentModel

Public Class FProcessing

    Private Sub FProcessing_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        FParse.Close()
        Timer1.Interval = 1000
        Timer1.Start()

    End Sub

    Private Sub Timer1_Timer(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        Label6.Text = myDLL.PUBLICVARIABLES.VAR1        Label3.Visible = Not Label3.Visible
        ProgressBar1.Maximum = 100 + myDLL.PUBLICVARIABLES.tot
        ProgressBar1.Value = 1 + myDLL.PUBLICVARIABLES.cpa
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        'If bg.WorkerSupportsCancellation = True Then
        'bw.CancelAsync()
        'End If

    End Sub

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Nasir Razzaq

5/14/2011

>Dim BackGroundWorker bgWorker
>Public FormB(BackGroundWorker worker)

That's a great blend of VB and C# code!

starlite551

5/15/2011

Sorry but I am not much familiar with VB.NET Syntax.. But I could have given better solution in C#

starlite551

5/15/2011

@hrodriguez761: Please post here the code for both the Forms A and B.. I shall convert the code to C#.NET and then solve the problem and convert it back to VB.NET.. As I am not much familiar with VB.NET to be honest.