I want to do BMI calculator. At the beginning it show weight 0 in Label, Height 0 in Label, Bmi NaN in Label i dont want to show number. How to fix it.

BmiViewModel.cs
public class BmiViewModel : INotifyPropertyChanged
{
private double height ;
private double weight ;
public event PropertyChangedEventHandler PropertyChanged;
private void RaisePropertyChanged(string propertyName)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
public double Height
{
get => height;
set
{
height = value;
RaisePropertyChanged(nameof(Bmi));
}
}
public double Weight
{
get => weight;
set
{
weight = value;
RaisePropertyChanged(nameof(Bmi));
}
}
public double Bmi
=> Math.Round(Weight / Math.Pow(Height /100, 2), 2);
}
BmiPage.xaml
<Label Text="BMI Calculator" Margin="20" TextColor="Black" FontSize="30" HorizontalTextAlignment="Center" />
<Entry Placeholder="Enter Weight" Text="{Binding Weight}" />
<Entry Placeholder="Enter Height" Text="{Binding Height}" />
<Label Text="Your BMI" FontSize="30"/>
<Label FontSize="30" Text="{Binding Bmi}" />