View source for Writing your own COM component using VB.NET

[[Category: COM integration]]

''Note: [[COM Integration|Calling a COM component]] requires {{Analytica Developer}} or higher.''

__TOC__

This article takes you through the steps of creating and writing your own COM component in VB.NET that can be called from Analytica. You can use your component to compute something and return the result, to interface with other applications, or to interact with the user.

To follow this example, you will also need to have
* Microsoft Visual Studio with VB  (I am using Visual Studio 2013)
* .NET Framework 4.0 or higher (I am using .NET 4.5).

== Using the component ==

In this example, we will create a component that accepts text and speaks it using a voice synthesizer. You would use this from your Analytica Model as follows.

:<code>Variable Speaker := COMCreateObject("AnaVoice.Speaker")</code>
:<code>Button RunIt</code>
::<code>OnClick: ''LongComputation'' ; Speaker->Say("The simulation has finished")</code>

== Creating the project ==

Steps:
# Start Visual Studio. 
#::To enable Visual Studio to register your component for you, you should launch it as Administrator. Right-click on the Visual Studio icon and select ''Run as administrator''.
# Select '''New Project...'''
# Select '''Visual Basic''' + '''Windows''' + '''Class Library''', and name your project (We've named this one <code>AnaVoice</code>).
#:[[image:VB_COM_New_Project.png]]
# From the menus, select '''Project''' / '''AnaVoice Properties''' / '''Compile'''.
#:Scroll down and check '''Register for COM interop'''
#:[[image:VB_COM_Register_for_COM_interop.png]]
# If you'll be using Analytica 64-bit, then from the menus select '''Build''' / '''Configuration Manager...'''.
#:In the table, change Any CPU to '''<New...>'''. New platform should say '''x64'''. Press '''OK'''.
#:[[image:VB_COM_Configuration_Manager.png]]
# In the '''Solution Explorer''' window, right click on the <code>Class1.vb</code> filename and change it to <code>AnaVoice.vb</code>.
#:[[image:VB_COM_Rename_File.png]]

== Defining and registering a class ==

With the project set up, you are ready to define the component interface. In the code window for <code>AnaVoice.vb</code>, enter this code:

<code style="background:white; border:white; margin-left: 1em;">
 <ComClass(Speaker.ClassId, Speaker.InterfaceId, Speaker.EventsId)>
 Public Class Speaker
    Public Const ClassId As String = "<font color="green">3A42F85E-24C8-4BAA-91B5-AE56C4683C13</font>"
    Public Const InterfaceId As String = "<font color="green">D99D7C79-2BA7-4A33-B7BC-9B7F19FDF828</font>"
    Public Const EventsId As String = "<font color="green">CA128AC4-580C-4112-9EAD-8D1599E3F37A</font>"
 
    Public Sub New()
        MyBase.New()
    End Sub
 
    Public Sub Say(ByVal phrase As String)
    End Sub
 End Class
</code>

::''Note: In C#, you'll need to add 
:::<code>using System.Runtime.InteropServices;</code> 
::at the top of your file.''

When creating your own component, be sure to replace the GUIDs that are in green above with unique GUIDs. To generate unique GUIDs, select '''Create GUID''' from the '''Tools''' menu, and use the ''Registry Format'' option. After copy and pasting, remove the curly braces so it looks like the code above.

You now have a complete project and API. Compile it by selecting '''Build''' / '''Rebuild Solution'''. This will build the project and register the component.

To validate that the component was actually registered, you can run RegEdit.exe and navigate to
:<code>HKEY_CLASSES_ROOT\AnaVoice.Speaker</code>

The method that you'll be calling from your Analytica model is 
:<code>    Public Sub Say(ByVal phrase As String)</code>
:<code>    End Sub</code>

Notice that the parameter is marked as <code>ByVal</code>. This is important -- Analytica's COM facility can only call methods that use <code>ByVal</code> parameters only, so do not declare any of your parameters as <code>ByRef</code>.

== Implementing the Method ==

Now we'll implement the <code>Say()</code> method to actually pronounce the phrase. Of course, in your own custom classes, this in where you would be implementing the logic that you are interested in.

# On the menus, select '''Project''' / '''Add Reference...'''
# On the left, select '''Assemblies''' / '''Framework'''
# In the main pane, scroll down and select '''System.Speech'''. Press '''OK'''
#:Note: If it isn't there, you don't have the .NET 4.0 or better Framework installed.
#:[[image:VB_COM_System_Speech.png|900px]]
# At the top of the ''AnaVoice.vb'' file, add these lines
#:<code>Imports System.Speech</code>
#:<code>Imports System.Speech.Synthesis</code>
# Enter the code for the body of the method
<pre style="background:white; border:white; margin-left: 1em;">
    Public Sub Speak(ByVal phrase As String)
        Dim synth As SpeechSynthesizer = New SpeechSynthesizer()
        Dim prompt As Prompt = New Prompt(phrase)
        synth.Speak(prompt)
    End Sub
</pre>
Your VB code is now complete. Compile it again ('''Build''' / '''Build Solution''').

== Test it ==

# Turn on your computer's speakers
# Start Analytica, edit mode, bring diagram to front.
# Create a variable named <code>Speaker</code> and set its definition to
#:<code>COMCreateObject("AnaVoice.Speaker")</code>
# Evaluate to test that it works. If it works (your component is properly registered) the result will be ''«COM Object»''
# In another variable [[Definition]] or Button [[OnClick]], call your method using
#:<code>Speaker->Say("Some text to say")</code>

You can use my test model, "[[media:AnaVoice test.ana|AnaVoice test.ana]]" shown here
:[[image:VB_COM_Test_Model.png]]

== See Also ==

* [[COM Integration]]
* [[media:AnaVoice.zip|AnaVoice.zip]]: The Visual Studio project files for this project.
* [[media:AnaVoice_test.ana|AnaVoice_test.ana]]: The test model that speaks a phrase that you enter from Analytica.