Question

I have two observalbe collections like below

public ObservableCollection<Employee> AllEmployees
{
  get { return _allEmployees; }
  set { _allEmployees = value;  }
}

public ObservableCollection<Employee> EmployeesToDisplay
{
   get { return _employeesToDisplay; }
   set { _employeesToDisplay = value;  }
}

They are both individually set by the value returned by wcf service.

                AllEmployees = ListofEmployees ;
                EmployeesToDisplay= ListofEmployees;

On change of a combobox that allows me to select Active employees or inactive employees I run the following Linq query on ‘AllEmployees’

var employeesEnabled = from entity in AllEmployees
where entity.IsEnabled == true
orderby entity.Name ascending
select entity;

and then assign the returned value to EmployeesToDisplay like below:

EmployeesToDisplay.Clear();
EmployeesToDisplay.Add(employeesEnabled as Employee);

The problem is:
When I go past this line ‘EmployeesToDisplay.Clear()’ … it even clears out ‘AllEmployees’

Any idea why this is happening? and how to get around it?

Thanks for your time…

Answer 1

Change your ‘set’ from ‘copy by reference’ to ‘copy by value’.

set { _employeesToDisplay = new ObservableCollection<Employee>( value );  }