control.invoke

control.invoke

• cbpd86

  Thank you all for your responses. I did get it working. Thanks again for your input.

  regards,

  woyler

  
  

• sobo1

  You have a delegate called Search of type MyEvents.

  You are calling Search.Invoke().

  Search is not a Control. It is a delegate.

  Delegate.Invoke and Control.Invoke are not the same.

  You need an instance of your form (which derives from Control). Call Invoke on that.

  
  
  

• JonM

  Chances are: you're not actually using Control.Invoke() for at least some control interaction.

  So, as Tim suggested, please post relevant code and stack trace so we can Identify the problem.

  Oh, by the way, any change this form was created on a worker thread < xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

  
  
  

• Kevin K.

  Please read the post. I used control.invoke. The result it gives me is the problem.

  
  

• DTXNA

  I thank you for your responses. I tried to strip out irrelevant code for readability. I hope it makes sense.
  Thanks in advance for all your help.

  
  'Global
  Delegate Sub MyEvents()

  Startup form:

  Private Sub frmMenu_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
  Dim thr As New Threading.Thread(AddressOf CreateConnection)
  thr.Start()
  end sub

  
  Public Sub CreateConnection()
  Dim sSend As String
  Try
  client.Connect(gsHost, giPort)
  nwStream = client.GetStream
  nwStream.BeginRead(readBuffer, 0, READ_BUFFER_SIZE, AddressOf DoRead, Nothing)
  sSend = ds_CommRequest.Connect & "|" & System.Net.Dns.GetHostName
  SendData(sSend)

  .......
  End Sub

  
  Private Sub DoRead(ByVal ar As IAsyncResult)
  Try
  Dim numBytesRead As Integer = nwStream.EndRead(ar)
  Dim returndata As String = Encoding.ASCII.GetString(readBuffer, 0, numBytesRead)
  If ProcessCommands(returndata) Then
  nwStream.BeginRead(readBuffer, 0, READ_BUFFER_SIZE, AddressOf DoRead, Nothing)
  End If
  End Try
  End Sub

  ////The ProcessCommands sub looks at the first char of the return data to determine what need to happen.
  Private Function ProcessCommands(ByVal strMessage As String) As Boolean
  Dim i_EventIndex As Int32 = 0
  Dim dataArray() As String
  Try

  dataArray = strMessage.Split(Chr(124))
  Select Case Convert.ToInt32(dataArray(0))
  Case 'Search
  MyClass.mo_ValueOne = dataarray(1)
  FireEvent(1) 'Search
  end select
  end try
  end function

  
  ////After is does that I pass an enum value to a FireEvent method of one of my classes. That code is below

  ////In this test my enum value denotes I am doing a search

  Sub FireEvent(byval _eventID as int16)
  '_eventId = Search

  Dim Search As MyEvents

  ''' I have a class that stores the instance of the forms as they are created called Forms
  ''' If I use Forms.Search.HandleSearchComplete (current instance of the Search form )
  ''' I will get the use control.invoke error
  Search = New MyEvents(AddressOf Forms.Search.HandleSearchComplete)

  
  ''' If I use frmSearch.HandleSearchComplete (just calling the sub with the form qualifier)
  ''' The code does not error out, but the value does not display on the loaded form
  Search = New MyEvents(AddressOf frmSearch.HandleSearchComplete)

  
  Search.Invoke()

  
  End Sub

  Class frmSearch
  Sub HandleSearchComplete()
  Try

  lblOne.Text = MyClass.mo_ValueOne

  Catch ex As Exception
  MessageBox.Show(ex.ToString)
  End Try
  End Sub
  end class

  //////////My startup form contains just command buttons. When I click on one,
  ////////// I create a form from the click event. I have a class to store the instance of each form

  
  Private Sub cmdLogSearch_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdLogSearch.Click
  If Forms.Search Is Nothing Then
  Dim fSearch As New frmSearch
  Forms.Search = fSearch
  End If
  Forms.Search.Show()
  Forms.Search.BringToFront()
  End Sub

  //// The form I am testing is a search form. below is the code for the search.

  Private Sub Search()
  Try
  SendData(ds_CommRequest.SearchByLog & "|" & txtLog.text)
  Catch ex As Exception
  MessageBox.Show(ex.ToString)
  Finally
  Cursor.Current = System.Windows.Forms.Cursors.Default
  End Try
  End Sub

  
  

• F.Costa

  you are going to need to post some code that shows what you are doing.

  
  
  

• PatK

  Please use Control.Invoke(). If you don't know what it is or how to use it, please look it up on MSDN or search this forum.

  
  
  

• Hardrock302

  I don't see any Control.Invoke() in this code. That's how it supposed to look (from http://msdn2.microsoft.com/en-us/library/zyzhdc6b.aspx):

  ' The following code assumes a 'ListBox' and a 'Button' control are added to a form,
  ' containing a delegate which encapsulates a method that adds items to the listbox.
  Public Class MyThreadClass
  Private myFormControl1 As MyFormControl
  
  Public Sub New(myForm As MyFormControl)
  myFormControl1 = myForm
  End Sub 'New
  
  Public Sub Run()
  ' Execute the specified delegate on the thread that owns
  ' 'myFormControl1' control's underlying window handle.
  myFormControl1.Invoke(myFormControl1.myDelegate)
  End Sub 'Run
  
  End Class 'MyThreadClass
  

  
  
  
• control.invoke