program crash when serverconnection is interrupted

Discussion in 'Questions (Windows Mobile)' started by schimanski, Jan 29, 2008.

  1. schimanski

    schimanski Well-Known Member Licensed User

    Hello!

    I have a problem with a server-connection. When the server-connection is interrupted, the application will crash. Only the task-manager can end the program. The Errorlabel can' catch this crash. The lines below are my source-code to get the data from the server:

    'Create the server-connection, when button is clicked'
    Sub Button4_Click
    ErrorLabel(noconnection)
    WaitCursor(true)
    client.New1 'init Client-Objekt'
    IP_Adresse=textbox18.Text
    Port_Nummer=textbox19.Text
    Client.Connect (IP_Adresse,Port_Nummer)

    If timer2.Enabled=false Then timer2.Enabled = true
    WaitCursor(false)
    Return
    noconnection:
    ..
    End Sub

    'Takes the data from the server'
    Sub Timer2_Tick
    ErrorLabel(connectionbreak)
    if ComboBox2.SelectedIndex = 1 then
    If client.DataAvailable=true Then
    Image4.LoadPicture("IconDaten1.bmp")
    filestream.New1(client.GetStream,false)
    GPS_Server.GPSStream(filestream.ReadString)
    Else
    Image4.LoadPicture("IconDaten2.bmp")
    End If
    else
    if client.DataAvailable=true then filesstream.Readstring
    End If
    Return

    connectionbreak:
    ..
    client.close
    End Sub


    thanks....:sign0085:
     
  2. agraham

    agraham Expert Licensed User

    I can't see why this would lock up, but is is a bit inefficient in that it New1's a filestream and loads a picture for every bit of data received. You may want to look at this code http://www.basic4ppc.com/forum/showthread.php?t=1130 that implements both a server and a client. I've tried killing the server and the client doesn't to lock up waiting for receive, it never sees any data available. It throws an error if the client tries to send after the server stops unexpectedly.

    Depending upon the implementation of the server and the TCP/IP stacks at each end what to the server seems a single send can arrive as several packets at the client. You are not assuming that a complete message always arrives intact as a single message are you?
     
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