Here's a quick walkthrough on creating your first VSTools project.

Open Visual Studio (the screen shots here are from VS 2008)

Choose FILE > NEW > PROJECT

You should see something like the below. If not, you haven't installed VS Tools correctly. Go back to the install documentation.

When it opens, you'll have a project with one class, GpAddin.vb. The code will look like this:

Imports Microsoft.VisualBasic
Imports System
Imports System.Collections
Imports System.Collections.Generic
Imports Microsoft.Dexterity.Bridge
Imports Microsoft.Dexterity.Applications


Public Class GPAddIn
    Implements IDexterityAddIn


    ' IDexterityAddIn interface


    Sub Initialize() Implements IDexterityAddin.Initialize


    End Sub


End Class

Here's the first thing that you should try:

 Imports Microsoft.VisualBasic
Imports System
Imports System.Collections
Imports System.Collections.Generic
Imports Microsoft.Dexterity.Bridge
Imports Microsoft.Dexterity.Applications


Public Class GPAddIn
    Implements IDexterityAddIn


    ' IDexterityAddIn interface


    Sub Initialize() Implements IDexterityAddin.Initialize
        AddHandler Dynamics.Forms.SopEntry.SopEntry.OpenAfterOriginal, AddressOf test


    End Sub


    Sub test(ByVal sender As Object, ByVal e As System.EventArgs)
        MsgBox("hello world")
    End Sub
End Class

Build your project, and copy the contents of the DEBUG folder to Dynamics/GP/addins. Launch Dynamics and open the SOP entry form, you should see the message box that we coded above.

The method that you're calling has to have a specific signature. The signature varies by the event that you're trapping. If it is a 'before' event, you'll have a 'cancelEventArgs' param. You can get the signature like this:

Coding custom (modified) objects 

Next, we'll add an event handler for some specific custom events - we'll add a custom button and text box can code up events for that.  

Add a button and a custom field to a form through Modifier. Here, I've added a supervisor field and lookup button to the Payroll Employee Maintenance form

After adding the button and text field, close Dynamics and run dag.exe to create the modified forms dictionary. Here's the line that I use:

dag.exe 0 "C:\Program Files\Microsoft Dynamics\GP\Dynamics.set" /M
pause

You'll get this:

This process is VERY memory intensive. You'll need 2 gb or risk a timeout or crash.

After this runs, you'll have two new files in the Dynamics/GP folder: Application.MicrosoftDynamicsGP.xml and Application.MicrosoftDynamicsGP.dll. Copy these files to your bin folder and set a reference to them.