There is no way to directly link a donation form to a calendar event; however, there are some solutions that may meet your needs:
  • Option 1: Append source codes to the donation form and calendar event: 
    1. Setup a donation form and configure both the donation form and the calendar event links to include the same source code information
    2. Run a transaction details report and include the source code field in the report
    3. Use the report to compare and contrast where the donations came from
  • Option 2: Allow attendees to make an additional donation (ticketed events only):
    1. Select Content > Events
    2. Click Edit in the Actions column
    3. Select Edit Ticket Information
    4. Mark the checkbox for "Yes, display the Additional Gift field on the ticket purchase page for this event" 
    5. Click Save