I have a series of form inputs with the same name (columnFilter) which when empty are not described in the form collection in my ASP.NET Core code

My request form payload as show in network tools is as follows

searchInput:
page: 1
exportformat: csv
columnFilter: 8
columnFilter:
columnFilter:
columnFilter: 66
currentSortKey: 1542182193
currentSortAscending: True
model: 0YjjzoiQiO3....

But when I inspect the form value for columnFilter in IFormCollection it shows me “8,66” what I would really like to see is “8,,,66”. That is, let me know that the 2nd and 3rd columnFilter values are empty. I can’t see a way to get that information ?