I'm writing a simple windows form app that a) sends a message b) has an event
handler for receiving that message and c) can check a queue for any messages
that are yet un-handled.
For some reason, the event handler is firing the event onMessage(), but the
text of the incoming message is lost.
Public Sub sendOne()
producer = session.CreateProducer(destination)
producer.Persistent = True
Dim message As ActiveMQTextMessage
message = session.CreateTextMessage("w00t!")
message.NMSCorrelationID = "abc"
producer.Send(message)
End Sub
(Works, and when I run this through the debugger I can see the text of the
message no problem with a breakpoint at the producer.Send line - so the text
has not been lost yet.)
Sub New(ByVal arg1 As Form1)
mainform = arg1
factory = New ConnectionFactory(New Uri("tcp://10.78.78.1:61636"))
connection = factory.CreateConnection()
session = connection.CreateSession()
destination = session.GetQueue("lyceum")
consumer = session.CreateConsumer(destination)
AddHandler consumer.Listener, AddressOf gotOne
mainform.setStatus("listener added.")
End Sub
This successfully adds an event handler gotOne to my class.
Private Sub gotOne(ByVal message As NMS.IMessage)
Dim amqMessage As ActiveMQTextMessage
amqMessage = CType(message, ActiveMQTextMessage)
mainform.setStatus("Got one.")
mainform.setMessages("begin" + amqMessage.Text + "end")
End Sub
gotOne works - I can see the "Got one." message and I see the "begin" when a
message comes in. But the original message is gone (debugger shows the
contents of amqMessage.Text as "") and for some odd reason the word "end"
does not show up. I put begin and end there just in case there were tab or
space characters I wasn't seeing. I've tried amqMessage.toString, which did
show me lots of information about the message, but the text of the message
was still not present. I was suspecting that it's the conversion from
IMessage to ActiveMQTextMessage but I have other code examples that seem to
indicate that I've done that correctly.
Any ideas?
The only weird thing about our setup I can think of is that I had to import
the Visual Studio 2005 source code of the .NET client available on this site
to Visual Studio 2003 to make it usable in our projects. But I've
successfully used these DLL's in other projects, and the above behavior did
not exhibit itself.
Here's the full source code:
Imports ActiveMQ
Imports NMS
Imports ActiveMQ.Commands
Public Class Form1
Inherits System.Windows.Forms.Form
#Region " Windows Form Designer generated code "
Dim L As Object
Public Sub New()
MyBase.New()
'This call is required by the Windows Form Designer.
InitializeComponent()
'Add any initialization after the InitializeComponent() call
End Sub
'Form overrides dispose to clean up the component list.
Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
If disposing Then
If Not (components Is Nothing) Then
components.Dispose()
End If
End If
MyBase.Dispose(disposing)
End Sub
'Required by the Windows Form Designer
Private components As System.ComponentModel.IContainer
'NOTE: The following procedure is required by the Windows Form Designer
'It can be modified using the Windows Form Designer.
'Do not modify it using the code editor.
Friend WithEvents lbStatus As System.Windows.Forms.ListBox
Friend WithEvents lbMessages As System.Windows.Forms.ListBox
Friend WithEvents Button1 As System.Windows.Forms.Button
Friend WithEvents Button2 As System.Windows.Forms.Button
<System.Diagnostics.DebuggerStepThrough()> Private Sub
InitializeComponent()
Me.lbStatus = New System.Windows.Forms.ListBox
Me.lbMessages = New System.Windows.Forms.ListBox
Me.Button1 = New System.Windows.Forms.Button
Me.Button2 = New System.Windows.Forms.Button
Me.SuspendLayout()
'
'lbStatus
'
Me.lbStatus.Location = New System.Drawing.Point(0, 8)
Me.lbStatus.Name = "lbStatus"
Me.lbStatus.Size = New System.Drawing.Size(656, 173)
Me.lbStatus.TabIndex = 0
'
'lbMessages
'
Me.lbMessages.HorizontalScrollbar = True
Me.lbMessages.Location = New System.Drawing.Point(0, 184)
Me.lbMessages.Name = "lbMessages"
Me.lbMessages.Size = New System.Drawing.Size(656, 329)
Me.lbMessages.TabIndex = 1
'
'Button1
'
Me.Button1.Location = New System.Drawing.Point(688, 48)
Me.Button1.Name = "Button1"
Me.Button1.TabIndex = 2
Me.Button1.Text = "DeQueue"
'
'Button2
'
Me.Button2.Location = New System.Drawing.Point(688, 88)
Me.Button2.Name = "Button2"
Me.Button2.TabIndex = 3
Me.Button2.Text = "Send One"
'
'Form1
'
Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
Me.ClientSize = New System.Drawing.Size(800, 517)
Me.Controls.Add(Me.Button2)
Me.Controls.Add(Me.Button1)
Me.Controls.Add(Me.lbMessages)
Me.Controls.Add(Me.lbStatus)
Me.Name = "Form1"
Me.Text = "Form1"
Me.ResumeLayout(False)
End Sub
#End Region
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
setStatus("Initialized.")
L = New ML(Me)
End Sub
Sub setStatus(ByVal message As String)
If lbStatus.Items.Count = 100 Then lbStatus.Items.RemoveAt(99)
lbStatus.Items.Insert(0, Now & " " & message)
End Sub
Sub setMessages(ByVal message As String)
If lbMessages.Items.Count = 100 Then lbMessages.Items.RemoveAt(99)
lbMessages.Items.Insert(0, Now & " " & message)
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click
L.goGetEm()
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button2.Click
L.sendOne()
End Sub
End Class
Imports ActiveMQ
Imports ActiveMQ.Commands
Imports NMS
Imports System
Public Class ML
Dim factory As IConnectionFactory
Dim connection As IConnection
Dim session As ISession
Dim destination As IDestination
Dim listener As MessageListener
Dim mainform As Form1
Dim consumer As IMessageConsumer
Dim producer As IMessageProducer
Sub New(ByVal arg1 As Form1)
mainform = arg1
factory = New ConnectionFactory(New Uri("tcp://10.78.78.1:61636"))
connection = factory.CreateConnection()
session = connection.CreateSession()
destination = session.GetQueue("lyceum")
consumer = session.CreateConsumer(destination)
AddHandler consumer.Listener, AddressOf gotOne
mainform.setStatus("listener added.")
End Sub
Public Sub sendOne()
producer = session.CreateProducer(destination)
producer.Persistent = True
Dim message As ActiveMQTextMessage
message = session.CreateTextMessage("w00t!")
message.NMSCorrelationID = "abc"
producer.Send(message)
End Sub
Private Sub gotOne(ByVal message As NMS.IMessage)
Dim amqMessage As ActiveMQTextMessage
amqMessage = CType(message, ActiveMQTextMessage)
mainform.setStatus("Got one.")
mainform.setMessages("begin" + amqMessage.Text + "end")
End Sub
Public Sub goGetEm()
'// lets consume a message
'ActiveMQTextMessage message = (ActiveMQTextMessage)
consumer.Receive();
'if (message == null)
'{
'Console.WriteLine("No message received!");
'}
'Else
'{
'Console.WriteLine("Received message with ID: " +
message.NMSMessageId);
'Console.WriteLine("Received message with text: " + message.Text);
'}
Dim message = New ActiveMQTextMessage
message = Me.consumer.Receive
If message Is Nothing Then
mainform.setStatus("No message waiting.")
Else
mainform.setMessages(message.text)
Dim fileWriter As New System.IO.StreamWriter("c:\file.txt")
fileWriter.Write(message.text)
fileWriter.Close()
End If
End Sub
End Class
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