public CategoryFilterView()
{
InitializeComponent();
// Define Filter that must be use.
EqualFilterInitializer initializer = new EqualFilterInitializer();
// Get FilterPresenter that connected to default collection view for Workspace.This.Products collection.
FilterPresenter productsCollectionViewFilterPresenter = FilterPresenter.TryGet(Workspace.This.Products);
// Get EqualFilter that use Category item property.
EqualFilter filter = ((EqualFilter)(productsCollectionViewFilterPresenter.TryGetFilter("Category", initializer)));
// Use instance of EqualFilter as Model.
Model = filter;
}
private void UserControl_DataContextChanged(object sender, DependencyPropertyChangedEventArgs e)
{
if (filter is not null)
{
filter.PropertyChanged -= filter_PropertyChanged;
filter = null;
}
if (e.NewValue is OrdersVm vm)
{
FilterPresenter fpr = FilterPresenter.Get(vm.OrdersCollectionView);
;
if (fpr.TryGetFilter("Employee", new EqualFilterInitializer(), out filter))
{
#pragma warning disable CS8602 // Dereference of a possibly null reference.
VisualStateManager.GoToState(this, filter.IsActive ? "Filtered" : "Unfiltered", false);
filter.PropertyChanged += filter_PropertyChanged;
#pragma warning restore CS8602 // Dereference of a possibly null reference.
}
}
}
private void UserControl_DataContextChanged(object sender, DependencyPropertyChangedEventArgs e)
{
OrdersVm vm = e.NewValue as OrdersVm;
if (vm != null)
{
FilterPresenter fpr = FilterPresenter.TryGet(vm.OrdersCollectionView);
filter = fpr.TryGetFilter("Employee", new EqualFilterInitializer());
if (filter != null)
{
if (filter.IsActive)
{
VisualStateManager.GoToState(this, "Filtered", false);
}
else
{
VisualStateManager.GoToState(this, "Unfiltered", false);
}
filter.PropertyChanged += filter_PropertyChanged;
}
}
}