CollectionView.Filter, propriété

public virtual Predicate<Object> Filter { get; set; }

/** @property */
public Predicate<Object> get_Filter ()

/** @property */
public void set_Filter (Predicate<Object> value)

public function get Filter () : Predicate<Object>

public function set Filter (value : Predicate<Object>)

Vous ne pouvez pas utiliser cette propriété dans XAML.

Valeur de la propriété

Simpler implementations do not support filtering and will throw a NotSupportedException. Use the CanFilter property to test if filtering is supported before assigning this property with a non-null value.

This example shows how to filter data in a view.

To create a filter, define a method that provides the filtering logic. The method is used as a callback and accepts a parameter of type object. The following method returns all the Order objects with the filled property set to "No", filtering out the rest of the objects.

public bool Contains(object de)
{
    Order order = de as Order;
    //Return members whose Orders have not been filled
    return(order.Filled== "No");
}

You can then apply the filter, as shown in the following example. In this example, myCollectionView is a ListCollectionView object.

myCollectionView.Filter = new Predicate<object>(Contains);

To undo filtering, you can set the Filter property to référence Null (Nothing en Visual Basic):

myCollectionView.Filter = null;

For information about how to create or obtain a view, see How to: Create a View of a Data Collection. For the complete example, see Sorting and Filtering Items in a View Sample.

If your view object comes from a CollectionViewSource object, you apply filtering logic by setting an event handler for the Filter event. In the following example, listingDataView is an instance of CollectionViewSource.

listingDataView.Filter += new FilterEventHandler(ShowOnlyBargainsFilter);

The following shows the implementation of the example ShowOnlyBargainsFilter filter event handler. This event handler uses the Accepted property to filter out AuctionItem objects that have a CurrentPrice of $25 or greater.

private void ShowOnlyBargainsFilter(object sender, FilterEventArgs e)
{
    AuctionItem product = e.Item as AuctionItem;
    if (product != null)
    {
        // Filter out products with price 25 or above
        if (product.CurrentPrice < 25)
        {
            e.Accepted = true;
        }
        else
        {
            e.Accepted = false;
        }
    }
}

For the complete example, see Data Binding Demo.

Microsoft .NET Framework 3.0 est pris en charge sur Windows Vista, Microsoft Windows XP SP2 et Windows Server 2003 SP1.

.NET Framework