How to pass multiple parameters in thread in VB

Question

I m looking to pass two or more parameters to a thread in VB 2008   The following method  modified  works fine without parameters  and my status bar gets updated very cool-y  But I can t seem to make it work with one  two or more parameters   This is the pseudo code of what I m thinking should happen when the button is pressed   Private Sub Btn Click     Dim evaluator As New Thread AddressOf Me testthread goodList  1   evaluator Start    Exit Sub   This is the testthread method   Private Sub testthread ByRef goodList As List Of OneItem   ByVal coolvalue As Integer       StatusProgressBar Maximum   100000     While  coolvalue  lt  100000          coolvalue   coolvalue   1         StatusProgressBar Value   coolvalue         lblPercent Text   coolvalue  amp              Me StatusProgressBar Refresh       End While  End Sub

User · Answer

Just create a class or structure that has two members, one List(Of OneItem) and the other Integer and send in an instance of that class.

Edit: Sorry, missed that you had problems with one parameter as well. Just look at Thread Constructor (ParameterizedThreadStart) and that page includes a simple sample.

User · Answer

Well  the straightforward method is to create an appropriate class structure which holds all your parameter values and pass that to the thread   Another solution in VB10 is to use the fact that lambdas create a closure  which basically means the compiler doing the above automatically for you   Dim evaluator As New Thread Sub                                   testthread goodList  1                              End Sub

User · Answer

Pass multiple parameter for VB NET 3 5    Public Class MyWork      Public Structure thread Data                     Dim TCPIPAddr As String         Dim TCPIPPort As Integer                 End Structure      Dim STthread Data As thread Data     STthread Data TCPIPAddr    192 168 2 2      STthread Data TCPIPPort   80        Dim multiThread As Thread   New Thread AddressOf testthread      multiThread SetApartmentState ApartmentState MTA      multiThread Start STthread Data            Private Function testthread ByVal STthread Data As thread Data           Dim IPaddr as string   STthread Data TCPIPAddr         Dim IPport as integer   STthread Data TCPIPPort          Your work              End Function  End Class

User · Answer

First of all  AddressOf just gets the delegate to a function - you cannot specify anything else  i e  capture any variables    Now  you can start up a thread in two possible ways    Pass an Action in the constructor and just Start   the thread  Pass a ParameterizedThreadStart and forward one extra object argument to the method pointed to when calling  Start parameter     I consider the latter option an anachronism from pre-generic  pre-lambda times - which have ended at the latest with VB10   You could use that crude method and create a list or structure which you pass to your threading code as this single object parameter  but since we now have closures  you can just create the thread on an anonymous Sub that knows all necessary variables by itself  which is work performed for you by the compiler    Soo      Dim Evaluator   New Thread Sub   Me TestThread goodList  1     It s really just that

User · Answer

In addition to what Dario stated about the Delegates you could execute a delegate with several parameters   Predefine your delegate   Private Delegate Sub TestThreadDelegate ByRef goodList As List Of String   ByVal coolvalue As Integer    Get a handle to the delegate  create parameters in an array  DynamicInvoke on the Delegate   Dim tester As TestThreadDelegate   AddressOf Me testthread Dim params 1  As Object params 0    New List Of String  params 1    0  tester DynamicInvoke params

User · Answer

I think this will help you     Creating Threads and Passing Data at Start Time   Imports System Threading    The ThreadWithState class contains the information needed for    a task  and the method that executes the task   Public Class ThreadWithState       State information used in the task       Private boilerplate As String      Private value As Integer         The constructor obtains the state information       Public Sub New text As String  number As Integer          boilerplate   text         value   number     End Sub         The thread procedure performs the task  such as formatting        and printing a document       Public Sub ThreadProc           Console WriteLine boilerplate  value      End Sub   End Class     Entry point for the example      Public Class Example     Public Shared Sub Main             Supply the state information required by the task           Dim tws As New ThreadWithState                 This report displays the number  0     42             Create a thread to execute the task  and then            start the thread           Dim t As New Thread New ThreadStart AddressOf tws ThreadProc           t Start           Console WriteLine  Main thread does some work  then waits            t Join           Console WriteLine                 Independent task has completed main thread ends        End Sub  End Class    The example displays the following output           Main thread does some work  then waits           This report displays the number 42           Independent task has completed  main thread ends

User · Answer

Dim evaluator As New Thread Sub   Me testthread goodList  1   With evaluator  IsBackground   True   not necessary     Start   End With

User · Answer

Something like this  I m not a VB programmer   Public Class MyParameters     public Name As String     public Number As Integer End Class    newThread as thread   new Thread  AddressOf DoWork  Dim parameters As New MyParameters parameters Name    Arne  newThread Start parameters    public shared sub DoWork byval data as object        dim parameters   CType data  Parameters

[vb.net] How to pass multiple parameters in thread in VB

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