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MVVM/WPF UI not update when executing method second time

I'm having troubles with my UI not updating when my properties change, even though I have INotifyPropertyChange applied. When i run the code the first time, it shows up correct and the UI is updated. While debbuging I can see the new values being set to the strings of the viewmodel and that the OnPropertChange event is fired, it just don't happen anything in the UI. The code below will be in order of events. As extra information, I use the same code to update the viewmodel both in the first and second time.
public partial class Transaktioner : Window
{
ViewModelCommon.ViewModel view = new ViewModelCommon.ViewModel();
private static List<ViewModelCommon.Items2> getAccountingRowsListEdited = new List<ViewModelCommon.Items2>();
{
DataContext = view;
InitializeComponent();
}
private async Task GetAccountinTransactionsAsync()
{
await Task.Run(() =>
{
getAccountingRowsList = client.GetAccountingTransactions(ftglist[index], 0, ref status).ToList();
foreach (var v in getAccountingRowsList)
{
getAccountingRowsListEdited.Add(new ViewModelCommon.Items2
{
itemName2 = v.ver.ToString(),
value2 = v.text,
vertyp = v.vtyp,
s2 = v.kto.ToString(),
s3 = v.trdat.ToString()
});
}
Task.Run(async () =>
{
await SearchAndDisplayResult();
});
});
}
private async Task SearchAndDisplayResult(int exclusion = 0)
{
await Task.Run(() =>
{
var verfikationer = getAccountingRowsListEdited.Where(u => u.vertyp != exclusion).Count(u => u.s2.ToString().Equals("0"));
view.VerifikationerTotal = verfikationer.ToString();
});
}
The ViewModel:
class ViewModelCommon
{
public abstract class ViewModelBase : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
protected bool SetProperty<T>(ref T field, T newValue, [CallerMemberName]string propertyName = null)
{
if (!EqualityComparer<T>.Default.Equals(field, newValue))
{
field = newValue;
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
return true;
}
return false;
}
protected virtual void OnPropertyChanged(string propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
protected void Test(string sb)
{
Transaktioner tr = new Transaktioner("");
tr.ExcludeStringChanged(sb);
}
}
public class ViewModel : ViewModelBase
{
private string _verifikationerTotal;
public string VerifikationerTotal
{
get { return _verifikationerTotal; }
set
{
if (value != _verifikationerTotal)
{
_verifikationerTotal = value;
OnPropertyChanged("VerifikationerTotal");
}
}
}
private string _ExcludeString;
public string ExcludeString
{
get { return _ExcludeString; }
set
{
if (value != _ExcludeString)
{
_ExcludeString = value;
OnPropertyChanged("ExcludeString");
Test(ExcludeString);
}
}
}
}
The WPF:
<TextBox x:Name="TextBoxVerifikationerTotal" Text="{Binding VerifikationerTotal}" IsEnabled="False" HorizontalAlignment="Left" Height="23" Margin="583,182,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="99"/>
<TextBox HorizontalAlignment="Left" Height="23" Margin="837,10,0,0" TextWrapping="Wrap" Text="{Binding Path=ExcludeString, Mode=TwoWay, UpdateSourceTrigger=LostFocus}" VerticalAlignment="Top" Width="286"/>
The code above works as expected.
In the UI there is an option to introduce the optional attribute to exclude values. Those are bound to the "ExludeString" this also works and fires the event passing it again to the SearchAndDisplayResult(int exclusion = 0) with the replaces value of the int being passed. While debugging I can see that the event can successfully find a new value and passing it to the ViewModel, but it doesn't update the UI.
Are there any thoughts on why the UI is not updated? Thank you in advance!
The code has been shortend to show the vitals

Answer for this case was the
ViewModelCommon.ViewModel view = new ViewModelCommon.ViewModel();
not being set to a private static while working with Tasks.

WPF INotifyPropertyChanged without burning base class

I'm trying to find a simple approach for data binding in WPF.
I'm using the INotifyPropertyChanged interface and it works fine if it's implemented on an abstract base class and inherited by objects that have bound members.
public partial class MainWindow : Window
{
public static MainWindow Instance;
private readonly Vm _vm;
public MainWindow ()
{
InitializeComponent();
DataContext = _vm = new Vm
{
Button1 = new Vm.ObservableButton(button1, new List<string> { "Paused", "Logging" }, false),
Button2 = new Vm.ObservableToggleButton(button2, new List<string> { "Log All", "Log VBA" }, false),
};
}
private class Vm
{
public abstract class ObservableObject : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged ([CallerMemberName] string propName = "")
{
var pc = PropertyChanged;
if (pc != null)
pc(this, new PropertyChangedEventArgs(propName));
}
}
public class ObservableButton : ObservableObject
{
private readonly Button _b;
private readonly List<string> _options;
private string _content;
public string Content
{
get { return _content; }
set
{
if (_content == value) return;
_content = value;
OnPropertyChanged();
}
}
public Boolean On { set; private get; }
public ObservableButton (Button b, List<string> options, Boolean on = true)
{
_b = b;
_options = options;
_b.Click += Click;
On = on;
Content = On ? _options[0] : _options[1];
}
public void Click (object sender, RoutedEventArgs e)
{
On = !On;
Content = On ? _options[0] : _options[1];
}
}
public class ObservableToggleButton : ObservableObject
{
private readonly ToggleButton _b;
private readonly List<string> _options;
private string _content;
public string Content
{
get { return _content; }
private set
{
if (_content == value) return;
_content = value;
OnPropertyChanged();
}
}
private Boolean _on;
public Boolean On
{
private get { return _on; }
set
{
if (_on == value) return;
_on = value;
Content = value ? _options[0] : _options[1];
}
}
public ObservableToggleButton (ToggleButton b, List<string> options, Boolean on = true)
{
_b = b;
_options = options;
On = on;
Content = _b.IsChecked ?? false ? _options[0] : _options[1];
}
public void Push ()
{
var peer = new ToggleButtonAutomationPeer(_b);
var toggleProvider = peer.GetPattern(PatternInterface.Toggle) as IToggleProvider;
if (toggleProvider != null) toggleProvider.Toggle();
//On = !On;
}
}
public ObservableButton Button1 { get; set; }
public ObservableToggleButton Button2 { get; set; }
public Vm ()
{
}
}
}
<Grid Margin="0,0,183,134">
<Button x:Name="button1" Content="{Binding Button1.Content}" HorizontalAlignment="Left" Margin="112,134,0,0" VerticalAlignment="Top" Width="75"/>
<ToggleButton x:Name="button2" IsChecked="{Binding Button2.On, Mode=OneWayToSource}" Content="{Binding Button2.Content}" HorizontalAlignment="Left" Margin="206,134,0,0" VerticalAlignment="Top"/>
</Grid>
I wanted to try doing this without burning the base class though, so I implemented INotifyPropertyChanged on the View Model and routed the change events from the bound members, back through the single interface on the View Model. Even though the Binding Object has a reference to the Source and the correct property name, this fails silently.
I figured that it doesn't work because the Binding Object does some type checking, so I made a fake implementation on the bound properties and it works. Here is the code for that scenario...
public partial class MainWindow : Window
{
public static MainWindow Instance;
public MainWindow ()
{
InitializeComponent();
DataContext = new ViewModel
{
Button1 = new ViewModel.ObservableButton(button1, new List<string> { "Paused", "Logging" }, false),
Button2 = new ViewModel.ObservableToggleButton(button2, new List<string> { "Log All", "Log VBA" }, false),
};
}
public class ViewModel : INotifyPropertyChanged
{
private static ViewModel _instance;
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged<T> (T control, [CallerMemberName] string propName = "")
{
var pc = PropertyChanged;
if (pc != null)
pc(control, new PropertyChangedEventArgs(propName));
}
public class ObservableButton : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged () {}
private readonly Button _b;
private readonly List<string> _options;
private string _content;
public string Content
{
get { return _content; }
set
{
if (_content == value) return;
_content = value;
_instance.OnPropertyChanged(this);
}
}
public Boolean On { set; private get; }
public ObservableButton (Button b, List<string> options, Boolean on = true)
{
_b = b;
_options = options;
_b.Click += Click;
On = on;
Content = On ? _options[0] : _options[1];
}
public void Click (object sender, RoutedEventArgs e)
{
On = !On;
Content = On ? _options[0] : _options[1];
}
}
public class ObservableToggleButton : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged () {}
private readonly ToggleButton _b;
private readonly List<string> _options;
private string _content;
public string Content
{
get { return _content; }
private set
{
if (_content == value) return;
_content = value;
_instance.OnPropertyChanged(this);
}
}
private Boolean _on;
public Boolean On
{
private get { return _on; }
set
{
if (_on == value) return;
_on = value;
Content = value ? _options[0] : _options[1];
}
}
public ObservableToggleButton (ToggleButton b, List<string> options, Boolean on = true)
{
_b = b;
_options = options;
On = on;
Content = _b.IsChecked ?? false ? _options[0] : _options[1];
}
}
public ObservableButton Button1 { get; set; }
public ObservableToggleButton Button2 { get; set; }
public ViewModel ()
{
_instance = this;
}
}
}
<Grid Margin="0,0,183,134">
<Button x:Name="button1" Content="{Binding Button1.Content}" HorizontalAlignment="Left" Margin="112,134,0,0" VerticalAlignment="Top" Width="75"/>
<ToggleButton x:Name="button2" IsChecked="{Binding Button2.On, Mode=OneWayToSource}" Content="{Binding Button2.Content}" HorizontalAlignment="Left" Margin="206,134,0,0" VerticalAlignment="Top"/>
</Grid>
So you can see that, even though the interface on the ObservableButton and ObservableToggleButton types are still routing the change notification through their parent, the Binding Object is happy because they toe the line on type.
Is there a good reason why the the child object needs to implement the interface even though there is already everything need to complete the binding without it?

I try to provide a clear example how this should be done in WPF instead of trying to fix the OP question.
XAML
<StackPanel>
<StackPanel.Resources>
<BooleanToVisibilityConverter x:Key="bToV" />
</StackPanel.Resources>
<!--bind the text to the viewmodel content. Use a bool to visibilty converter to convert from true to Visible-->
<TextBlock
Text="{Binding Path=Content}"
Visibility="{Binding Path=IsContentVisible, Converter={StaticResource bToV}}" />
<!--Use a two way binding to sync the IsChecked property with the viewmodel-->
<ToggleButton IsChecked="{Binding Path=IsContentVisible,Mode=TwoWay}"
Content="{Binding Path=ToogleActionName}" />
</StackPanel>
code behind
to keep your project structure clear I warmly suggest to put each class in a separate file. However I put all 3 classes into one single file for easier posting.
using System.ComponentModel;
using System.Runtime.CompilerServices;
using System.Windows;
namespace WpfApplication4
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = new ContentViewModel() { Content = "foo" };
}
}
public class ContentViewModel : ViewModelBase
{
private string _toogleActionName = "turn it off";
private bool _isContentVisible = true;
private string _content;
public bool IsContentVisible
{
get
{
return _isContentVisible;
}
set
{
_isContentVisible = value;
//switch action name
if (value)
ToogleActionName = "turn it off";
else
ToogleActionName = "turn it on";
OnPropertyChanged();
}
}
public string Content
{
get
{
return _content;
}
set
{
_content = value;
OnPropertyChanged();
}
}
public string ToogleActionName
{
get
{
return _toogleActionName;
}
set
{
_toogleActionName = value;
OnPropertyChanged();
}
}
}
public class ViewModelBase : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
}
I hope this is showing how WPF is supposed to work with the MVVM pattern.

The problem there is that the ViewModel on the first example:
private class Vm
{
...
}
Does not implement INofityPropertyChanged interface, therefore whenever you say that you DataContext is "Vm", the binding would not know that a property has changed because the view model it is not implementing INotifyPropertyChanged...
And on the second example, it is working because you are implementing a INofityPropertyChanged on the view model class
public class ViewModel : INotifyPropertyChanged
{
...
}
Note that it doesn't matter if your child classes implements INotifyPropertyChanged if your base class doesn't implement it too and your base class is observing changes on the children and raises the changes as "its own"...

Why can't I reflect a list box choice in a text box in WPF?

I'm new to WPF and I'm having some trouble with my existing setup to get the list box selected item to appear in the text box.
The picture here represents the issue. I typed "12 HOUR" in the text box, which then filters the listbox to those items with "12 HOUR" anywhere in the string. But when I click "12 Hour Nasal" in the list box, I now want to reflect that choice back in the text box:
http://i.imgur.com/ZCYAolT.png
Here is my XAML for the user control containing the listbox and textbox:
<UserControl x:Class="SCM_AllergyRecModule.SearchAndSelectView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d">
<StackPanel Width="300">
<TextBox x:Name="Filter" Text="{Binding Path=Filter, UpdateSourceTrigger=PropertyChanged}"/>
<ListBox Width ="300" Height="50" x:Name="ListBoxControl"
ItemsSource="{Binding Path=Allergens}"
SelectedItem="{Binding Path=SelectedAllergen}">
</ListBox>
</StackPanel>
And here is the ViewModel:
namespace SCM_AllergyRecModule
{
public class SearchAndSelectViewModel
{
private ICollectionView allergens;
private string selectedAllergen;
private string filter = "";
public string Filter
{
get
{
return this.filter.ToUpperInvariant();
}
set
{
if (this.filter != value)
{
this.filter = value;
this.Allergens.Refresh();
}
}
}
private bool ContainsFilter(object item)
{
var product = item as string;
if (product == null)
{
return false;
}
if (string.IsNullOrEmpty(this.Filter))
{
return true;
}
if (product.ToUpperInvariant().Contains(this.Filter))
{
return true;
}
return false;
}
public SearchAndSelectViewModel()
{
var cvs = new CollectionViewSource();
cvs.Source = MainWindow.scmAllergens;
this.allergens = cvs.View;
this.allergens.Filter = ContainsFilter;
}
public ICollectionView Allergens
{
get
{
return this.allergens;
}
}
public string SelectedAllergen
{
get
{
return this.selectedAllergen;
}
set
{
if (this.selectedAllergen != value)
{
this.selectedAllergen = value;
}
}
}
}
}
Update 1
I added the INotifyPropertyChanged interface to my class and have it being raised on SelectedAllergen in the setter. I added an event handler called SearchAndSelectViewModel_PropertyChanged to handle the SelectedAllergen property changing and set it in the constructor.
Now when I click an item in the listbox, I do see it setting the Filter to the SelectedItem and the list filters to that item so nothing else shows. But still, the text box text is not changing? See screenshot below. This is after I typed in "PEAN" in the textbox, then the listbox filtered to two choices, and I chose "PEANUTS (FOOD)", which then refiltered the list box to just show that choice but didn't set the text box to "PEANUTS (FOOD)":
http://imgur.com/dNxuVI5
Updated ViewModel
public class SearchAndSelectViewModel : INotifyPropertyChanged
{
private ICollectionView allergens;
private string selectedAllergen;
private string filter;
public string Filter
{
get
{
return this.filter.ToUpperInvariant();
}
set
{
if (this.filter != value)
{
this.filter = value;
this.Allergens.Refresh();
}
}
}
private bool ContainsFilter(object item)
{
var product = item as string;
if (product == null)
{
return false;
}
if (string.IsNullOrEmpty(this.Filter))
{
return true;
}
if (product.ToUpperInvariant().Contains(this.Filter))
{
return true;
}
return false;
}
private void SearchAndSelectViewModel_PropertyChanged(object sender, PropertyChangedEventArgs e)
{
switch (e.PropertyName)
{
case "SelectedAllergen":
this.Filter = this.SelectedAllergen;
break;
}
}
public SearchAndSelectViewModel()
{
filter = "";
var cvs = new CollectionViewSource();
cvs.Source = MainWindow.scmAllergens;
this.allergens = cvs.View;
this.allergens.Filter = ContainsFilter;
this.PropertyChanged += SearchAndSelectViewModel_PropertyChanged;
}
public ICollectionView Allergens
{
get
{
return this.allergens;
}
}
public string SelectedAllergen
{
get
{
return this.selectedAllergen;
}
set
{
if (this.selectedAllergen != value && value != null)
{
this.selectedAllergen = value;
OnPropertyChanged("SelectedAllergen");
}
}
}
// INotifyPropertyChanged implementation
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged(string propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
}

You need to implement the INotifyPropertyChanged interface and you can raise it in your property setter. Since you are also binding your TextBox to the Filter property you need to set the Filter property when your SelectedAllergen changes.
INotifyPropertyChanged example:
public class MyViewModel : INotifyPropertyChanged
{
//...
private int myProperty = 0;
public int MyProperty
{
get { return myProperty; }
set
{
myProperty = value;
// Raise the property changed notification
OnPropertyChanged("MyProperty");
}
}
// INotifyPropertyChanged implementation
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged(string propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if(handler != null)
{
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
}

Setting WPF Control from WCF Service

I am trying to set the name (textbox) value using WCF Service. I am hosting service in WPF application. I used the MVVM Model initially to set textbox value from the MainWindow.cs and it worked. But then I made some properties static in order to access the same through the service contract. It still seems to setting the property of Model attribute but not changing value in the text box. Can anyone please guide me?
Model.cs
public class Model : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged(string propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
protected bool SetField<T>(ref T field, T value, string propertyName)
{
if (EqualityComparer<T>.Default.Equals(field, value)) return false;
field = value;
OnPropertyChanged(propertyName);
MessageBox.Show(field.ToString());
return true;
}
// props
private static string testname;
public static string TestName
{
get { return testname; }
set {
Model m = new Model();
m.SetField(ref testname, value, "TestName");
}
}
}
WCF InameService.cs
public class nameService : InameService
{
public void setMyName(string name)
{
Model.TestName = name;
}
}
MainWindow.xaml
<Grid Name="GridName">
<TextBox Name="TextName" HorizontalAlignment="Left" Height="23" Margin="193,140,0,0" TextWrapping="Wrap" Text="{Binding TestName, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Top" Width="120" />
</Grid>
MainWindow.xaml.cs
public partial class MainWindow : Window
{
public MainWindow()
{
ServiceHost host = new ServiceHost(typeof(nameService));
InitializeComponent();
host.Open();
Model s = new Model();
//this.DataContext = s.NameValue.TestName;
Model.TestName = "Alicia";
this.TextName.DataContext = s;
}
}

Thanks Nathan for help. Following is the answer:
I changed the ViewModel to Singleton Class and also instantiated the composite Model object while creating the instance.
`class ViewModel
{
private static volatile ViewModel instance;
private static object _mutex = new object();
private ViewModel() { }
private Model model;
public Model NameValue
{
get { return model; }
set { model = value; }
}
public static ViewModel Instance
{
get
{
if (instance == null)
{
lock (_mutex)
{
if (instance == null)
{
instance = new ViewModel();
instance.model = new Model();
}
}
}
return instance;
}
}
}`
then changed the MainWindow.xaml.cs
try
{
ViewModel s = ViewModel.Instance;
s.NameValue.TestName = "Alicia";
this.DataContext = s;
this.TextName.DataContext = s;
}
catch (Exception e)
{
MessageBox.Show("Error" + e.Message);
}
Similar changes was done in the Service Contract Class. I hope this will help some one trying to get the value in

Don't use static properties as you can't bind to them. Use a static object instead or pass the Model object to the service for example in the constructor and use that instance for updates.
public class nameService : InameService
{
private Model model;
public nameService(Model m)
{
model = m;
}
public void setMyName(string name)
{
model.TestName = name;
}
}
public class Model : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged(string propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
protected bool SetField<T>(ref T field, T value, string propertyName)
{
if (EqualityComparer<T>.Default.Equals(field, value)) return false;
field = value;
OnPropertyChanged(propertyName);
MessageBox.Show(field.ToString());
return true;
}
// props
private string testname;
public string TestName
{
get { return testname; }
set {
Model m = new Model();
m.SetField(ref testname, value, "TestName");
}
}
}

INotifyPropertyChanged 'Double' binding

I'm trying to bind some XAML code to a property in my ViewModel.
<Grid Visibility="{Binding HasMovies, Converter={StaticResources VisibilityConverter}}">
...
</Grid>
My ViewModel is setup like this:
private bool _hasMovies;
public bool HasMovies
{
get { return _hasMovies; }
set { _hasMovies = value; RaisePropertyChanged("HasMovies"); }
}
In the constructor of the ViewModel, I set the HasMovies link:
MovieListViewModel()
{
HasMovies = CP.Connection.HasMovies;
}
in CP:
public bool HasMovies
{
get { return MovieList != null && MovieList.Count > 0; }
}
private ObservableCollection<Movie> _movies;
public ObservableCollection<Movie> MovieList
{
get { return _movies; }
set
{
_movies = value;
RaisePropertyChanged("MovieList");
RaisePropertyChanged("HasMovies");
_movies.CollectionChanged += MovieListChanged;
}
}
private void MovieListChanged(object sender, NotifyCollectionChangedEventArgs e)
{
RaisePropertyChanged("HasMovies");
}
What am I doing wrong? How should I change this binding so that it reflects the current state of CP.Connection.HasMovies?

Either directly expose the object in the ViewModel and bind directly through that (so that the value is not just copied once which is what happens now) or subscribe to the PropertyChanged event and set HasMovies to the new value every time it changes in your source object.
e.g.
CP.Connection.PropertyChanged += (s,e) =>
{
if (e.PropertyName = "HasMovies") this.HasMovies = CP.Connection.HasMovies;
};

First of all, the setter for a collection type, such as your MovieList property, is not called when you change the content of the collection (ie. Add/Remove items).
This means all your setter code for the MovieList property is pointless.
Secondly, it's very silly code. A much better solution, is to use NotifyPropertyWeaver. Then your code would look like this, in the viewmodel:
[DependsOn("MovieList")]
public bool HasMovies
{
get { return MovieList != null && MovieList.Count > 0; }
}
public ObservableCollection<Movie> MovieList
{
get;
private set;
}
Alternatively you would have to add a listener for the CollectionChanged event when you initialize the MovieList property the first time (no reason to have a backing property, really really no reason!), and then call RaisePropertyChanged("HasMovies") in the event handler.
Example:
public class CP : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
public CP()
{
MovieList = new ObservableCollection<Movie>();
MovieList.CollectionChanged += MovieListChanged;
}
public bool HasMovies
{
get { return MovieList != null && MovieList.Count > 0; }
}
public ObservableCollection<Movie> MovieList
{
get;
private set;
}
private void MovieListChanged(object sender, NotifyCollectionChangedEventArgs e)
{
RaisePropertyChanged("HasMovies");
}
private void RaisePropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}