vs2005 c#

how do i trap max number of row in a collection ?

lets say I can only have max of two rows in a collection

I have this property
       const int MaxCount_SubmitterEDIContactInfos = 2;
       private void validate_SubmitterEDIContactInfos()
       {
           if (_SubmitterEDIContactInfos.Count >
MaxCount_SubmitterEDIContactInfos)
               Set Field Error ( "Too many rows ...bla,bla          }
       private List<PER_EDIContact> _SubmitterEDIContactInfos;
       public List<PER_EDIContact> SubmitterEDIContactInfos
       {
           get { return _SubmitterEDIContactInfos; }

           set
           {
               _SubmitterEDIContactInfos = value;
               validate_SubmitterEDIContactInfos();
           }
       }

if i do 3 times
 SubmitterEDIContactInfos.Add(new PER_EDIContact(file[c++]));
SubmitterEDIContactInfos.Add(new PER_EDIContact(file[c++]));
SubmitterEDIContactInfos.Add(new PER_EDIContact(file[c++]));

the set property is not hit at all, why?

set is only hit from constructor constructor

       public SubmitterName()
       {
           SubmitterEDIContactInfos = new List<PER_EDIContact>();
       }