VBA script to combine all records in a sub-form into a usable string

Question

I am using the Outlook 15.0 Object Library to create emails and appointments.
I have a form that contains event information and subform that contains event participants (a related table).
Right now I am able to click a button that will take information from the Event table and one selected record at a time from the participants table. Some of the participants are instructors, some are staff. I only want to list instructors.
That code looks something like this:
.body = "Participants: <ul><li> " & [Forms]!MainForm!SubForm.Form![Participant]
This means I have to create three emails or manually type additional details.
What I am looking to do is do some sort of loop to combine these before inserting them into the .body code. Below is a sketch of what I want to happen, but again -- I'm not sure where to begin.
Dim Instructors as String
If [Subform].[Type] = "Instructor" Then
Add to Instructors & "</li><li>"
End if
.body = "Participants: <ul><li> " & Instructors & "</li></ul>"

Answer 1

You might like to take a look at the file Concat.zip in my public databases folder at:
https://onedrive.live.com/?cid=44CC60D7FEA42912&id=44CC60D7FEA42912!169
If you have difficulty opening the link copy its text (NB, not the link location) and paste it into your browser's address bar.
This little demo file includes a solution for concatenating values from a related table using the very efficient GetString method of the ADO recordset object to concatenate values.  As the example it uses data from Northwind.  In my file the function
is called in a report, but you could call it in your code to build a list of participants as a string expression.  If you want the participants listed on separate lines use the left hand column of my report as the example of how to call the function;
for a comma separated list use the right hand column.
Allen Brown also provides a concatenation function at:
http://allenbrowne.com/func-concat.html
which I believe loops through a DAO recordset to build the list.
Ken Sheridan, Stafford, England