C#/WPF: PropertyChanged for all Properties in ViewModel?

Question

I've a class like this:

public class PersonViewModel : ViewModelBase //Here is the INotifyPropertyChanged Stuff {     public PersonViewModel(Person person)     {         PersonEntity = person;     }      public Person PersonEntity {          get { return PersonEntity.Name; }         private set { PersonEntity.Name = value; RaisePropertyChanged("PersonEntity");     }      public string Name {          get { return PersonEntity.Name; }         set { PersonEntity.Name = value; RaisePropertyChanged("Name");     }      public int Age{          get { return PersonEntity.Age; }         set { PersonEntity.Age= value; RaisePropertyChanged("Age");     }       public void ChangePerson(Person newPerson)     {         //Some Validation..         PersonEntity = newPerson;     } 

My TextBoxes are bound to Name and Age of the ViewModel. If I change the _person object in the ViewModel, do I have to call for each Property a RaisePropertyChanged again or is there a way to do this automaticly (in my concret example I have about 15 Properties..)?

Thanks for any help.

Cheers Joseph

Answer 1

You can indicate all properties have changed by using null or string.Empty for the property name in PropertyChangedEventArgs. This is mentioned in the documentation for PropertyChanged.

Answer 2

One other solution I used to tackle the problem of: first setting the value and then calling the PropertyChangedEventArgs is by adding a Set function in my ViewModelBase which looks like this:

public class ViewModelBase : INotifyPropertyChanged {     protected bool Set<T>(ref T backingField, T value, [CallerMemberName] string propertyname = null)     {         // Check if the value and backing field are actualy different         if (EqualityComparer<T>.Default.Equals(backingField, value))         {             return false;         }          // Setting the backing field and the RaisePropertyChanged         backingField = value;         RaisePropertyChanged(propertyname);         return true;    } } 

Instead of doing this:

public string Name {      get { return PersonEntity.Name; }     set { PersonEntity.Name = value; RaisePropertyChanged("Name"); }  

You can now achieve the same by doing this:

public string Name {      get { return PersonEntity.Name; }     set { Set(ref PersonEntity.Name,value); }