c # – Set alternative records to true if its even number is equal to the last record

I have an attendance list like this.

problem: I need to put In and Outside alternately. but if I only have 3 records, then I have to set 0 recordings in real. 1 record is true. and 3 record is at once In Outside is false. I have tried that way it works well. but I was checking is there a better way

ObservableCollection participationsPerDay = new ObservableCollection();
if (participationsPerDay.Count% 2 == 0)
{
int counter = 0;
foreach (var attendance at PerDay audience)
{
if (counter% 2 == 0)
assistance.In = true;
other
assistance.Out = true;
counter ++;
}
}
other
{
int counter = 0;
foreach (var attendance at PerDay audience)
{
if (expectationsPerDay.IndexOf (presence) == expectationsPerDay.Count - 1)
Carry on;
if (counter% 2 == 0)
assistance.In = true;
other
assistance.Out = true;
counter ++;
}
}