Registering Procedure Trigger on VS Tools.

Dynamics GP Community Post

Example:

public static Microsoft.Dexterity.Applications.DynamicsDictionary.SopPoPreviewForm.FormProcedures poProc = Dynamics.Forms.SopPoPreview.Procedures;

public void Initialize()
        {  
               poProc.PoGetAddNewSuitable.InvokeAfterOriginal += PoGetAddNewSuitable_InvokeAfterOriginal;

        }

private void PoGetAddNewSuitable_InvokeAfterOriginal(object sender, Microsoft.Dexterity.Applications.DynamicsDictionary.SopPoPreviewForm.PoGetAddNewSuitableProcedure.InvokeEventArgs e)
        {
            //throw new NotImplementedException();
            
            MessageBox.Show(e.inParam1);

        }

PoGetAddNewSuitable procedure is called as many time as there are items on sales order, if you only need to capture sales document number and type then look for other procedure, although you will have these value from this procedure as well but your code will run each time procedure will be called.