Getting Started

For demonstration purposes all project / code examples will be using Visual Basic .Net 2005. Note that this document is intended for HL7 professionals, it is beyond the scope of this document to explain what HL7 is and how it is implemented. It is assumed that you have a basic understanding of the HL7 message structure and data requirements at least as it pertains to your particular objective. Feel free to contact customer service (US#254-549-0825) to discuss your project requirements and goals. We will be more than happy to give you our opinion (for free and worth 10x what you pay for it) of whether anything within our arsenal of HL7 tools would be beneficial and how.

Step 2. Add a reference to the toolkit DLL (filename: UPLTK.Net2005.dll). Note that you will have to "browse" for the DLL when adding the reference.

Step 3. In your main form add 2 buttons, 1 textbox and 1 richtextbox. Also add some labels as shown below. Our objective here is to create an application which allows you to a) enter the port number you will be receiving HL7 messages on into textbox1 b) click the 'Start Receiving Messages' button to begin c) echo anything received into RichTextbox1 and d) allow you to stop receiving messages by clicking the 'Stop Receiving Messages' button.

Step 4. In the code view (declarations section) declare your Proxy object and some variables.

'The Listener Proxy Toolkit Object

Private WithEvents MyListener As New UPLTK.Net2005.ListenerProxy

'Some miscellaneous variables we'll use to keep score

Private nMessagesReceived As Long = 0

Private dtLastMessage As Date

Private strLastControlID As String = ""

Private strLastSendingApplication As String = ""

Private strLastType As String = ""

Private strLastEvent As String = ""

Step 5. Since the events raised by the Proxy object might be coming in from another thread and since we're in Windows Form we need a thread safe way to update our richtextbox.

Delegate Sub ChangeControlTextDelegate(ByVal ctrl As RichTextBox, _

ByVal text As String)

'The method with the delegate signature

'Provides cross-thread safe response to events in this case using

'a RichTextBox control

Private Sub ChangeControlText(ByVal ctrl As RichTextBox, _

ByVal text As String)

If Me.InvokeRequired Then

Me.Invoke(New ChangeControlTextDelegate(AddressOf ChangeControlText), _

New Object() {ctrl, text})

Return

End If

Dim buff$

Try

buff$ = Now.ToString & " " & text & Environment.NewLine

With ctrl

If .TextLength > 50000 Then .Text = ""

.SelectionStart = 0

.SelectionLength = 0

.SelectedText = buff$

End With

Catch ex As Exception

MessageBox.Show(ex.Message, "Error Tracing", MessageBoxButtons.OK, MessageBoxIcon.Error)

End Try

End Sub

Private Sub Trace(ByVal strMessage As String)

'This is multi-thread safe

ChangeControlText(RichTextBox1, strMessage)

'This is not

'Dim buff as String

'Try

' buff = Now.ToString & " " & strMessage & Environment.Newline

' With RichTextBox1

' .SelectionStart = 0

' .SelectionLength = 0

' .SelectedText = buff

' End With

'Catch ex As Exception

' MsgBox(ex.ToString)

'End Try

End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

With MyListener

If .IsListening() Then

Button2.Enabled = True

MessageBox.Show("The listener is running!", "Error", MessageBoxButtons.OK)

Exit Sub

End If

.ClearErrors()

RichTextBox1.Text = ""

Trace("Starting the listener")

Try

Dim i As Integer

i = CInt(TextBox1.Text.Trim())

'Verify that it's a valid port number

If i < 1 Or i > (1024 * 64) Then

MessageBox.Show("Invalid port number!", "Error", MessageBoxButtons.OK)

Exit Sub

End If

If Not MyListener.StartListening(i) Then

MessageBox.Show(MyListener.LastError, "Error From Object", MessageBoxButtons.OK, MessageBoxIcon.Error)

'Enable the Stop Listener Button

Button2.Enabled = True

Exit Sub

End If

Button2.Enabled = True

Catch ex As Exception

MessageBox.Show(ex.Message, "System Error", MessageBoxButtons.OK, MessageBoxIcon.Error)

Button2.Enabled = True

End Try

End With

End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click

Try

With MyListener

If .IsListening Then

.StopListening()

End If

Button2.Enabled = False

End With

Catch ex As Exception

MessageBox.Show(ex.Message)

End Try

End Sub

Private Sub MyListener_ConnectionAccepted() Handles MyListener.ConnectionAccepted

Trace("A connection was accepted!")

End Sub

Private Sub MyListener_ConnectionDropped() Handles MyListener.ConnectionDropped

Trace("A connection was dropped")

End Sub

Private Sub MyListener_ListenerStarted() Handles MyListener.ListenerStarted

Trace("The listener started!")

End Sub

Private Sub MyListener_ListenerStopped(ByVal strMessage As String) Handles MyListener.ListenerStopped

Trace("The listener stopped!")

End Sub

Private Sub MyListener_HL7MessageReceived(ByRef objHL7Message As UPLTK.Net2005.ProxyHL7Message) Handles MyListener.HL7MessageReceived

Try

Dim sBuff As String = ""

With objHL7Message

nMessagesReceived += 1

dtLastMessage = System.DateTime.Now

strLastControlID = .HL7MSH_ControlID

strLastSendingApplication = .HL7MSH_SendingApplication

strLastType = .HL7MSH_MessageType

strLastEvent = .HL7MSH_MessageEvent

sBuff = .ThisHL7Message 'The entire HL7 message

End With

Trace("HL7 Message Received: " & Environment.NewLine & sBuff)

'Update some of our scorekeeping labels

lblMessageCount.Text = nMessagesReceived.ToString

sBuff = dtLastMessage.ToShortTimeString & " From [" & _

strLastSendingApplication & "] Type/Event [" & _

strLastType & "/" & strLastEvent & _

"] Control # [" & strLastControlID & "]"

lblDetail.Text = sBuff

Catch ex As Exception

End Try

End Sub