Handle property change event listeners (lots of them) more elegantly (dictionary?)
- by no9
hELLO !
Here i have a simple class example with three fields of type class B and some other stuff.
As you can see im listening on every child object change.
Since i could need alot of properties of type class B i wonder if there is a way of shrinking the code. Creating a listener + a method for each seems like i will have ALOT of code. How would i fix this ... using a dictionary or something similar? I have been told that IoC could fix this, but im not sure where to start.
public class A : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
public int _id;
public int Id
{
get { return _id; }
set
{
if (_id == value)
{
return;
}
_id = value;
OnPropertyChanged("Id");
}
}
public string _name;
public string Name
{
get { return _name; }
set
{
if (_name == value)
{
return;
}
_name = value;
OnPropertyChanged("Name");
}
}
public B _firstB;
public B FirstB
{
get { return _firstB; }
set
{
if (_firstB == value)
{
return;
}
if (_firstB != null)
{
FirstB.PropertyChanged -= firstObjectB_Listener;
}
_firstB = value;
if (_firstB != null)
FirstB.PropertyChanged += new PropertyChangedEventHandler(firstObjectB_Listener);
OnPropertyChanged("FirstB");
}
}
public B _secondB;
public B SecondB
{
get { return _secondB; }
set
{
if (_secondB == value)
{
return;
}
if (_secondB != null)
{
FirstB.PropertyChanged -= secondObjectB_Listener;
}
_secondB = value;
if (_secondB != null)
SecondB.PropertyChanged += new PropertyChangedEventHandler(secondObjectB_Listener);
OnPropertyChanged("FirstB");
}
}
public B _thirdB;
public B ThirdB
{
get { return _thirdB; }
set
{
if (_thirdB == value)
{
return;
}
if (_thirdB != null)
{
ThirdB.PropertyChanged -= thirdObjectB_Listener;
}
_thirdB = value;
if (_thirdB != null)
ThirdB.PropertyChanged += new PropertyChangedEventHandler(thirdObjectB_Listener);
OnPropertyChanged("ThirdB");
}
}
protected void OnPropertyChanged(string name)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(name));
}
}
void firstObjectB_Listener(object sender, PropertyChangedEventArgs e)
{
Console.WriteLine("Object A has found a change of " + e.PropertyName + " on first object B");
}
void secondObjectB_Listener(object sender, PropertyChangedEventArgs e)
{
Console.WriteLine("Object A has found a change of " + e.PropertyName + " on second object B");
}
void thirdObjectB_Listener(object sender, PropertyChangedEventArgs e)
{
Console.WriteLine("Object A has found a change of " + e.PropertyName + " on third object B");
}
}
