Use the collection editor to set a property
In the Properties panel, you can set properties in many ways. At the simplest level, you can enter a value, select a button, or select a value from a drop-down list. More complex properties use the subproperty and collection editors. You can also use advanced property options to data bind, template bind, or apply a resource to a property.
The following procedure shows you how to use a collection editor to set the BitmapEffect property. You can set the BitmapEffect property to a single effect, or a collection of effects. If you set the property to a collection of effects, then you use the collection editor to add effects to the collection.
To use the collection editor to set a property
Select an object on the artboard, such as a button or a rectangle.
Under Appearance in the Properties panel, click the Show advanced properties button to expand the Appearance category.
Beside the BitmapEffect property, click the drop-down arrow next to the New button, and then select BitmapEffect Group. This sets the BitmapEffect property to an empty collection of possible effects.
Next to the new Children subproperty, click the Edit items in this collection button.
The collection editor opens.
To add a bitmap effect to the collection, click the Add another item button.
In the Select Object window, the applicable objects are listed under System.Windows.Media.Effects. Select one of the objects (such as BevelBitmapEffect) and then click OK.
Back in the collection editor, the bitmap effect that you selected is added under Items. You can add more bitmap effects to the collection, and you can set the properties for each child bitmap effect on the right side of the collection editor under Properties. When you finish, click OK.
To add or modify a property that has a collection of child properties, click the Edit items in this collection button next to the Children property in the Properties panel. If instead you click the New button next to the BitmapEffect property, your collection will be replaced with a new property setting.