delay sending data

[ZeroEffect]

I am trying to implement a delay when send data. Because of this delay I will need to queue any data received while waiting for the delay to expire. I have everything set up I am using System.collections Queue for holding the data received while the delay is active. Once the delay has expired I check the queue and then process that data. I have all of this working. To create the delay I am processsing the data in a new thread then inside that thread I am using that thread sleep function. This works too but while this thread is sleeping then main thread sleeps too.

 

here is my test code.

 

Imports System.Threading
Imports System.Collections

Public Class Form1
   Private Delegate Sub tbCall(ByVal tb As TextBox)

   Dim rp1Q As Queue
   Dim tRP1 As Thread
   Dim blntRP1 As Boolean = False

   Shared Sub Main()
       Application.Run(New Form1())
   End Sub

   Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
       rp1Q = New Queue(10)
       wsRecData.Bind()
   End Sub

   Private Sub wsRecData_DataArrival(ByVal sender As Object, ByVal e As AxMSWinsockLib.DMSWinsockControlEvents_DataArrivalEvent) Handles wsRecData.DataArrival
       Dim strData As Object
       wsRecData.GetData(strData)
       TextBox2.AppendText(Now & vbTab & BuildString(strData) & vbCrLf)
       ProcessData(BuildString(strData))
   End Sub

   Private Function BuildString(ByVal strData As Array) As String
       Dim temp As Long, mString As String
       mString = ""
       For temp = 0 To UBound(strData)
           mString &= Chr(strData(temp))
       Next
       Return mString
   End Function

   Private Sub ProcessData(ByVal tempData As String)
       tempData = Replace(tempData, "|", "") 'Remove Pipe
       tempData = Replace(tempData, "^", "") 'Remove Carot

       'add to cue and start processing
       'if data is to be forwarded.
       'if port is enabled cue data and start processing.
       rp1Q.Enqueue(tempData)
       If blntRP1 = False Then
           tRP1 = New Thread(AddressOf processRP1)
           tRP1.IsBackground = True
           tRP1.Start()
       End If

   End Sub

   Private Sub processRP1()
       Dim tempData As String
       blntRP1 = True
       If TextBox1.InvokeRequired Then
           Dim LogsafeSub As New tbCall(AddressOf processRP1)
           TextBox1.Invoke(LogsafeSub, TextBox1)
       Else
           Do While rp1Q.Count > 0
               'pause if there is a delay
               tRP1.Sleep(7000)

               tempData = rp1Q.Dequeue()

               wsSendData.SendData(Now & vbTab & tempData & vbCrLf)
           Loop
           blntRP1 = False
       End If
   End Sub

   Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
       TextBox1.Clear()
       TextBox2.Clear()
   End Sub
End Class

 

Data from this application is sent correctly it is delayed 7 seconds for each item in the queue. but durring this time the main application is frozen.

 

Any thoughts?

 

Thanks

 

ZeroEffect

 

yes I will be switching to sockets when move away from the test application.

[ZeroEffect]

Re: delay sending data *update*

 

So for the heck of it I added this line to my project to see what happened.

 

Control.CheckForIllegalCrossThreadCalls = False

 

and everything worked like I wanted it to. It looks like my issue has to due with haveing to use delagates and the [controlname].invoke for cross thread access to the controls and when the thread sleeps the whole thing sleeps. I know it is not a good coding to not check for these cross thread calls does anyone have a better solution?

 

Thanks for your help,

 

ZeroEffect

[ZeroEffect]

Re: delay sending data *update*

 

Any thoughts on this?

[Nate Bross]

This code

If TextBox1.InvokeRequired Then
   Dim LogsafeSub As New tbCall(AddressOf processRP1)
   TextBox1.Invoke(LogsafeSub, TextBox1)        
Else

 

Is making the sub processRP1 execute on the same thread that TextBox1 was created (the UI thread).

[ZeroEffect]

After many months of other projects I am able to com back to this. I was able to solve my problem by using a background worker. Now I have another seemingly sime issue and this has to do with time. I need to delay the data "x" amount of time from when it is received. sound simple. eh?

 

let say I have a delay of 7 seconds converted to milliseconds (7000)

 

data is received at 00:00:20 data out at 00:00:27

 

if any data is received durring the delay time it is added to a cue to be processed after the delayed data is over. In a perfect world there should be no data receieved durring the delay.

 

if any data came in between 00:00:20 and 00:00:27 the delay would be 7 seconds from the time it was received and not 7 second from the last time data was sent.

 

I am looking for suggestions for getting this delay and coverting it into the correct milliseconds.

 

I was thinking (#seconds to delay - ([time in] - [current time])) * 1000)

 

First event might look like this

 

(7 - (00:00:20 - 00:00:20) ) * 1000

(7 - 0) * 1000

7 * 1000 = 7000

 

I should not be doing math when I am tired LOL

 

Thanks for your thoughts.

 

ZeroEffect