Using MSMQ in Dot Net Using VB.Net Sending and Receiving Messages Using MSMQ in Dot Net:

Using MSMQ in Dot Net Using VB.Net
Sending and Receiving Messages Using MSMQ in Dot Net:

author: Sreedhar Koganti 

This example will help you to know how to send and receive messages using MSMQ. 

In Dot net, MSMQ provides a powerful set of services. These you can get from 

System.Messaging name space. In order to use MSMQ explorer our 

Dot Net IDE can also be used to add and remove messages form MSMQ.



How you can use MSMQ:

 In order to use MSMQ first you have to install MSMQ in your machine.

        Since we are looking at MSMQ in Dot Net, 

you need to have Windows 2000 + Service Pack1, MSMQ, .NET Framework Beta1 and 

Visual Studio.NET .



How to Use MSMQ:

MSMQ Enterprise can be managed through the MSMQ Explorer. 

The MSMQ Explorer provides an interface for managing all machines in a 

MSMQ environment from a single point of control. This MSMQ Explorer 

you can get from Computer Management/Services and Applications/MessageQueing.



  Here I am trying to show a simple Example in VS.Net(VB).

In this example I am using a Windows Application in the C# Environment.

This example will help you to know how to send and receive messages using MSMQ.

In this example I am basically using System.Messaging name space to manage the 

messages using msmq.



To do that created a Windows application in VB using VS.net.



In that i take a form module and I kept two buttons one for sending

data and one for receiving data. And I also used a text box.While sending

message i am taking message form the textbox.Button one is used to send message.

Other button will be used to receive the data. 



To use the MSMQ name space System.Messaging, you have to go to Tools and 

Component Tab, then Drag and Drop the MessageQueue to the Form (Design View).

Once you add it, as shown below, code will be added to your application



Private WithEvents MessageQueue1 As System.Messaging.MessageQueue

The above code will be added in   public class Form1 : System.WinForms.Form

and one more important line 

Me.MessageQueue1 = New System.Messaging.MessageQueue()

will be added in Private Sub InitializeComponent()



While your application initializes it will create the messageQueue1 .

Once your object has been Created or Instantiated you can use it's methods and 
Properties.



In our example we are trying to Send a message to "Smile" Pirvate Queue.

"Smile"is a Queue name which we are using in the example. It's not a system Queue.



The code below is used for sending the message to a queue when you click Button1 
button.



****************************

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs)

        Dim q As MessageQueue

        If MessageQueue.Exists(".Private$Smile") Then

            q = New MessageQueue(".Private$Smile")

        Else

            q = MessageQueue.Create(".Private$Smile")

        End If

        

        Dim BW As New BinaryWriter(New MemoryStream())

        bw.Write(textbox1.Text)

        Dim m As New Messaging.Message()

        m.BodyStream = BW.BaseStream

        m.Label = "Sri Test Message"

        

        q.Send(m)

        msgbox("Message sent successfully", 
                 Microsoft.VisualBasic.MsgBoxStyle.Information, 
"MSMQ Message")

        

    End Sub  

******************************



When you click the command one first i am checking for Queue if queue is not 
there

then i am creating the Queue , if queue is the i am sending the message to the 
queue

usingn Send method.

Send Can basically will have two arguments a) Message b) Label for that message.



Button Two will help you to receive the messages:

******************************

Protected Sub Button2_Click(ByVal sender As Object, ByVal e As System.EventArgs)

        Dim q As MessageQueue

        Dim m As Messaging.Message

        Dim Br As BinaryReader

        Dim x As String

        

        If MessageQueue.Exists(".Private$Smile") Then

            q = New MessageQueue(".Private$Smile")

        Else

            q = MessageQueue.Create(".Private$Smile")

        End If

        

        

        Try

            m = q.Receive(New TimeSpan(0, 0, 3))

            Br = New BinaryReader(m.BodyStream)

            x = New String(Br.ReadChars(CInt(m.BodyStream.Length)))

        Catch

            x = "(no message)"

            

        End Try

        msgbox(x, Microsoft.VisualBasic.MsgBoxStyle.Information, "MSMQ Message")

        

    End Sub

********************************

If you look into the code, basically I am testing for the existence of the Smile 
Private Queue.

If it is not there, I am popping up a message box. If it is there, then I am 
instantiating

a PostMessage as a Message Queue.



Here I have to explain one thing. The message object holds the result of the 
received message.

So here I am using m as the message object, and we also created a TimeSpan object 
from the

System name space. The TimeSpan object will tell how long to wait for the Receive

method before timing out (hours, minutes, seconds).

Before .Net, we could simply set a message object Body property to a string value.

But in Dot Net the data will be automatically wrapped in XML using SOAP encoding.

It makes consistent with other languages with in  Dot Net. 



Note:

Take care with the following Steps:

 1. Must install MSMQ on your machine.

 2. Drag and Drop the Message Queue into your Design Form.

 3. You must be using System.Messaging;

 4. Must declare a message for receiving messages. Here we declared as m.

 5. Build the code before running.





Author:

Sreedhar Koganti

Working in Unisys as a Technical Team Lead

Expertixe in ASP,COM+,XML,SOAP,NTService,VB, Drop of .Net

Article Writer in asptoday.com,Aspalliance.com,aspfree.com

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