Count checkboxes v3.6.0

Let’s assume we want to allow a maximum of 2 selections.

• Boolean columns write true & false values. The number interpretation will be 1 & 0. A simple sum aggreation on the column will suffice to get the count.
  
  
• If there are at least 2 selected rows, we want to disable all other checkboxes (no further selections can be made, but existing ones can be unchecked)
  

Rule Cycle

Let’s take a quick look at the rule execution cycle (row & data updates)

• Checkbox clicked
• [1] User input will:
  • Reset row data on the changed row (background color, overwrite data, etc.)
  • trigger a row update check, the total value is still 1 at this point
• [2] All other update events are done, the data update rule will calculate the new totals
  

We can add another step to this cycle, by selecting the Rerun after data update option in the row update trigger
This will trigger another row update on all rows once the data updates are done.

Further thoughts:

• This is not required for row group totals, they already trigger the row update on the row group
  
• With the rerun option enabled on any rule, an additional check on all rows will be executed. This might degrade overall performance.