Filtering C1CollectionView

With C1CollectionView you can filter a collection to produce a new sub-set containing exactly those elements of the original collection for which a given predicate returns true. When you filter a C1CollectionView, the underlying data set is not affected. The Filter property gets or sets a callback used to determine if an item is suitable for inclusion in the view.

For example, you can set a predicate to the Filter property and this will cause the list to be filtered by that predicate.

Visual Basic	Copy Code
' create an observable list of customers Dim list = New System.Collections.ObjectModel.ObservableCollection(Of Customer)() ' create a C1CollectionView from the list _view = New C1.Xaml.C1CollectionView(list) ' filter by country = Austria. Customers not from Austria will be filtered out. _view.Filter = Sub(item As Object) Dim c As Customer = TryCast(item, Customer) If c IsNot Nothing Then If c.Country.Equals("Austria") Then Return True End If End If Return False End Sub

Visual Basic

Copy Code

' create an observable list of customers
Dim list = New System.Collections.ObjectModel.ObservableCollection(Of Customer)()

' create a C1CollectionView from the list
_view = New C1.Xaml.C1CollectionView(list)

' filter by country = Austria. Customers not from Austria will be filtered out.
_view.Filter = Sub(item As Object)
Dim c As Customer = TryCast(item, Customer)
If c IsNot Nothing Then
      If c.Country.Equals("Austria") Then
            Return True
      End If
End If
Return False
End Sub

C#	Copy Code
// create an observable list of customers var list = new System.Collections.ObjectModel.ObservableCollection<Customer>(); // create a C1CollectionView from the list _view = new C1.Xaml.C1CollectionView(list); // filter by country = Austria. Customers not from Austria will be filtered out. _view.Filter = delegate(object item) { Customer c = item as Customer; if (c != null) { if (c.Country.Equals("Austria")) return true; } return false; };

Copy Code

// create an observable list of customers
var list = new System.Collections.ObjectModel.ObservableCollection<Customer>();

// create a C1CollectionView from the list
_view = new C1.Xaml.C1CollectionView(list);

// filter by country = Austria. Customers not from Austria will be filtered out.
_view.Filter = delegate(object item)
{
    Customer c = item as Customer;
    if (c != null)
    {
        if (c.Country.Equals("Austria"))
            return true;
    }
    return false;
};

Note: If the collection implements INotifyCollectionChanged any changes to the data will be applied to the filter even after it’s been set.

For an advanced example of filtering, see the Filter sample for FlexGrid for UWP: https://www.grapecity.com/en/samples/flexgrid-samples.