variable value set in MVVM in WPF

[Prahlad]

I have a Dto File in which I get the value. Now I need it in another file in the variable that I access from the get-set but the value is 0. The original value does not come. My code is as follows.

Dto.cs

 public int RemainingVisits => NoOfVisit - UsageCount ;

File0ne.cs
constructor

SelectedPlan = new PlanDto();

get-set

private PatientPlanDto selectedPlan;

        public PatientPlanDto SelectedPlan
        {
            get => selectedPlan;
            set
            {
                selectedPlan = value;                                
            }
        }

pass 0(error code)

if (SelectedPlan.RemainingVisits>0)
            {
                //code
            }

Any one help...