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UsesItemPolicyAttribute Class

Restricts a feature provider to a specified policy.

Inheritance Hierarchy

System.Object
  System.Attribute
    Microsoft.Windows.Design.RequirementAttribute
      Microsoft.Windows.Design.Policies.UsesItemPolicyAttribute

Namespace:  Microsoft.Windows.Design.Policies
Assembly:  Microsoft.Windows.Design.Interaction (in Microsoft.Windows.Design.Interaction.dll)

Syntax

'Declaration
<AttributeUsageAttribute(AttributeTargets.Class, AllowMultiple := True)> _
Public NotInheritable Class UsesItemPolicyAttribute _
    Inherits RequirementAttribute
[AttributeUsageAttribute(AttributeTargets.Class, AllowMultiple = true)]
public sealed class UsesItemPolicyAttribute : RequirementAttribute
[AttributeUsageAttribute(AttributeTargets::Class, AllowMultiple = true)]
public ref class UsesItemPolicyAttribute sealed : public RequirementAttribute
[<Sealed>]
[<AttributeUsageAttribute(AttributeTargets.Class, AllowMultiple = true)>]
type UsesItemPolicyAttribute =  
    class
        inherit RequirementAttribute
    end
public final class UsesItemPolicyAttribute extends RequirementAttribute

The UsesItemPolicyAttribute type exposes the following members.

Constructors

  Name Description
Public method UsesItemPolicyAttribute Initializes a new instance of the UsesItemPolicyAttribute class.

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Properties

  Name Description
Public property AllRequired Overrides the RequirementAttribute.AllRequired property to return false. (Overrides RequirementAttribute.AllRequired.)
Public property ItemPolicyType Gets the type of policy the feature provider can be associated with.
Public property TypeId Gets the type ID for this attribute. (Overrides Attribute.TypeId.)

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Methods

  Name Description
Public method CreateSubscription Returns a RequirementSubscription object that can be used to be notified when this policy is available. (Overrides RequirementAttribute.CreateSubscription(EditingContext).)
Public method Equals Determines whether the specified object is equal to this UsesItemPolicyAttribute. (Overrides Attribute.Equals(Object).)
Protected method Finalize Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public method GetHashCode Returns the hash code for this attribute. (Overrides Attribute.GetHashCode().)
Public method GetType Gets the Type of the current instance. (Inherited from Object.)
Public method IsDefaultAttribute When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
Public method Match When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Public method MeetsRequirement Returns a value indicating whether the specified editing context contains the ItemPolicyType associated with this attribute instance. (Overrides RequirementAttribute.MeetsRequirement(EditingContext).)
Protected method MemberwiseClone Creates a shallow copy of the current Object. (Inherited from Object.)
Public method ToString Returns a string that represents the current object. (Inherited from Object.)

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Explicit Interface Implementations

  Name Description
Explicit interface implemetationPrivate method _Attribute.GetIDsOfNames Maps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetationPrivate method _Attribute.GetTypeInfo Retrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetationPrivate method _Attribute.GetTypeInfoCount Retrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetationPrivate method _Attribute.Invoke Provides access to properties and methods exposed by an object. (Inherited from Attribute.)

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Remarks

Not all extensions support policies.

Examples

The following code example shows how to attach a custom surrogate policy to a feature provider by using UsesItemPolicyAttribute. For a full code listing, see How to: Create a Surrogate Policy.

' The DockPanelAdornerProvider class implements an adorner
' that you can use to set the Margin property by using a 
' drag operation. The DockPanelPolicy class enables a 
' container policy for offering additional tasks and 
' adorners on the panel's children.
<UsesItemPolicy(GetType(DockPanelPolicy))>  _
Class DockPanelAdornerProvider
    Inherits AdornerProvider

    Public Sub New() 
        ' The adorner is a Rectangle element.
        Dim r As New Rectangle()
        r.Width = 23.0
        r.Height = 23.0
        r.Fill = AdornerColors.GlyphFillBrush

        ' Set the rectangle's placement in the adorner panel.
        AdornerPanel.SetAdornerHorizontalAlignment(r, AdornerHorizontalAlignment.OutsideLeft)
        AdornerPanel.SetAdornerVerticalAlignment(r, AdornerVerticalAlignment.OutsideTop)

        Dim p As New AdornerPanel()
        p.Children.Add(r)

        AdornerPanel.SetTask(r, New DockPanelMarginTask())

        Adorners.Add(p)
    End Sub
End Class
// The DockPanelAdornerProvider class implements an adorner
// that you can use to set the Margin property by using a 
// drag operation. The DockPanelPolicy class enables a 
// container policy for offering additional tasks and 
// adorners on the panel's children.
[UsesItemPolicy(typeof(DockPanelPolicy))]
class DockPanelAdornerProvider : AdornerProvider
{
    public DockPanelAdornerProvider() 
    {
        // The adorner is a Rectangle element.
        Rectangle r = new Rectangle();
        r.Width = 23.0;
        r.Height = 23.0;
        r.Fill = AdornerColors.GlyphFillBrush;

        // Set the rectangle's placement in the adorner panel.
        AdornerPanel.SetAdornerHorizontalAlignment(r, AdornerHorizontalAlignment.OutsideLeft);
        AdornerPanel.SetAdornerVerticalAlignment(r, AdornerVerticalAlignment.OutsideTop);

        AdornerPanel p = new AdornerPanel();
        p.Children.Add(r);

        AdornerPanel.SetTask(r, new DockPanelMarginTask());

        Adorners.Add(p);
    }
} 

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

See Also

Reference

Microsoft.Windows.Design.Policies Namespace

ItemPolicy

SelectionPolicy

FeatureProvider

FeatureConnectorAttribute

Other Resources

Feature Providers and Feature Connectors

Understanding WPF Designer Extensibility