TaskbarItemInfo Class

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Represents information about how the taskbar thumbnail is displayed.

Inheritance Hierarchy

System.Object
  System.Windows.Threading.DispatcherObject
    System.Windows.DependencyObject
      System.Windows.Freezable
        Microsoft.Windows.Shell.TaskbarItemInfo

Namespace:  Microsoft.Windows.Shell
Assembly:  Microsoft.Windows.Shell (in Microsoft.Windows.Shell.dll)

Syntax

'Declaration
Public NotInheritable Class TaskbarItemInfo _
    Inherits Freezable

public sealed class TaskbarItemInfo : Freezable

public ref class TaskbarItemInfo sealed : public Freezable

[<Sealed>]
type TaskbarItemInfo =  
    class
        inherit Freezable
    end

public final class TaskbarItemInfo extends Freezable

The TaskbarItemInfo type exposes the following members.

Constructors

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

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Properties

  Name Description
Public property CanFreeze Gets a value that indicates whether the object can be made unmodifiable. (Inherited from Freezable.)
Public property DependencyObjectType Gets the DependencyObjectType that wraps the CLR type of this instance.  (Inherited from DependencyObject.)
Public property Description Gets or sets the text for the taskbar item tooltip.
Public property Dispatcher Gets the Dispatcher this DispatcherObject is associated with. (Inherited from DispatcherObject.)
Public property IsFrozen Gets a value that indicates whether the object is currently modifiable. (Inherited from Freezable.)
Public property IsSealed Gets a value that indicates whether this instance is currently sealed (read-only). (Inherited from DependencyObject.)
Public property Overlay Gets or sets the image that is displayed over the program icon in the taskbar button.
Public property ProgressState Gets or sets a value that indicates how the progress indicator is displayed in the taskbar button.
Public property ProgressValue Gets or sets a value that indicates the fullness of the progress indicator in the taskbar button.
Public property ThumbButtonInfos Gets or sets the collection of ThumbButtonInfo objects that are associated with the Window.
Public property ThumbnailClipMargin Gets or sets a value that specifies the part of the application window's client area that is displayed in the taskbar thumbnail.

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Attached Properties

  Name Description
Public attached property TaskbarItemInfo Gets or sets a TaskbarItemInfo that is attached to a window.

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Methods

  Name Description
Public method CheckAccess Determines whether the calling thread has access to this DispatcherObject. (Inherited from DispatcherObject.)
Public method ClearValue(DependencyProperty) Clears the local value of a property. The property to be cleared is specified by a DependencyProperty identifier. (Inherited from DependencyObject.)
Public method ClearValue(DependencyPropertyKey) Clears the local value of a read-only property. The property to be cleared is specified by a DependencyPropertyKey. (Inherited from DependencyObject.)
Public method Clone Creates a modifiable clone of the Freezable, making deep copies of the object's values. When copying the object's dependency properties, this method copies expressions (which might no longer resolve) but not animations or their current values. (Inherited from Freezable.)
Protected method CloneCore Makes the instance a clone (deep copy) of the specified Freezable using base (non-animated) property values. (Inherited from Freezable.)
Public method CloneCurrentValue Creates a modifiable clone (deep copy) of the Freezable using its current values. (Inherited from Freezable.)
Protected method CloneCurrentValueCore Makes the instance a modifiable clone (deep copy) of the specified Freezable using current property values. (Inherited from Freezable.)
Public method CoerceValue Coerces the value of the specified dependency property. This is accomplished by invoking any CoerceValueCallback function specified in property metadata for the dependency property as it exists on the calling DependencyObject. (Inherited from DependencyObject.)
Protected method CreateInstance Initializes a new instance of the Freezable class. (Inherited from Freezable.)
Protected method CreateInstanceCore When implemented in a derived class, creates a new instance of the Freezable derived class. (Inherited from Freezable.)
Public method Equals Determines whether a provided DependencyObject is equivalent to the current DependencyObject. (Inherited from DependencyObject.)
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 Freeze Makes the current object unmodifiable and sets its IsFrozen property to true. (Inherited from Freezable.)
Protected method FreezeCore Makes the Freezable object unmodifiable or tests whether it can be made unmodifiable. (Inherited from Freezable.)
Public method GetAsFrozen Creates a frozen copy of the Freezable, using base (non-animated) property values. Because the copy is frozen, any frozen sub-objects are copied by reference. (Inherited from Freezable.)
Protected method GetAsFrozenCore Makes the instance a frozen clone of the specified Freezable using base (non-animated) property values. (Inherited from Freezable.)
Public method GetCurrentValueAsFrozen Creates a frozen copy of the Freezable using current property values. Because the copy is frozen, any frozen sub-objects are copied by reference. (Inherited from Freezable.)
Protected method GetCurrentValueAsFrozenCore Makes the current instance a frozen clone of the specified Freezable. If the object has animated dependency properties, their current animated values are copied. (Inherited from Freezable.)
Public method GetHashCode Gets a hash code for this DependencyObject. (Inherited from DependencyObject.)
Public method GetLocalValueEnumerator Creates a specialized enumerator for determining which dependency properties have locally set values on this DependencyObject. (Inherited from DependencyObject.)
Public methodStatic member GetTaskbarItemInfo Gets the value of the TaskbarItemInfo attached property for an object.
Public method GetType Gets the Type of the current instance. (Inherited from Object.)
Public method GetValue Returns the current effective value of a dependency property on this instance of a DependencyObject. (Inherited from DependencyObject.)
Public method InvalidateProperty Re-evaluates the effective value for the specified dependency property (Inherited from DependencyObject.)
Protected method MemberwiseClone Creates a shallow copy of the current Object. (Inherited from Object.)
Protected method OnChanged Called when the current Freezable object is modified. (Inherited from Freezable.)
Protected method OnFreezablePropertyChanged(DependencyObject, DependencyObject) Ensures that appropriate context pointers are established for a DependencyObjectType data member that has just been set. (Inherited from Freezable.)
Protected method OnFreezablePropertyChanged(DependencyObject, DependencyObject, DependencyProperty) This member supports the Windows Presentation Foundation (WPF) infrastructure and is not intended to be used directly from your code. (Inherited from Freezable.)
Protected method OnPropertyChanged Overrides the DependencyObject implementation of OnPropertyChanged to also invoke any Changed handlers in response to a changing dependency property of type Freezable. (Inherited from Freezable.)
Public method ReadLocalValue Returns the local value of a dependency property, if it exists. (Inherited from DependencyObject.)
Protected method ReadPreamble Ensures that the Freezable is being accessed from a valid thread. Inheritors of Freezable must call this method at the beginning of any API that reads data members that are not dependency properties. (Inherited from Freezable.)
Public methodStatic member SetTaskbarItemInfo Sets the value of the TaskbarItemInfo attached property for an object.
Public method SetValue(DependencyProperty, Object) Sets the local value of a dependency property, specified by its dependency property identifier. (Inherited from DependencyObject.)
Public method SetValue(DependencyPropertyKey, Object) Sets the local value of a read-only dependency property, specified by the DependencyPropertyKey identifier of the dependency property. (Inherited from DependencyObject.)
Protected method ShouldSerializeProperty Returns a value that indicates whether serialization processes should serialize the value for the provided dependency property. (Inherited from DependencyObject.)
Public method ToString Returns a string that represents the current object. (Inherited from Object.)
Public method VerifyAccess Enforces that the calling thread has access to this DispatcherObject. (Inherited from DispatcherObject.)
Protected method WritePostscript Raises the Changed event for the Freezable and invokes its OnChanged method. Classes that derive from Freezable should call this method at the end of any API that modifies class members that are not stored as dependency properties. (Inherited from Freezable.)
Protected method WritePreamble Verifies that the Freezable is not frozen and that it is being accessed from a valid threading context. Freezable inheritors should call this method at the beginning of any API that writes to data members that are not dependency properties. (Inherited from Freezable.)

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Events

  Name Description
Public event Changed Occurs when the Freezable or an object it contains is modified. (Inherited from Freezable.)

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Fields

  Name Description
Public fieldStatic member DescriptionProperty Identifies the Description dependency property.
Public fieldStatic member OverlayProperty Identifies the Overlay dependency property.
Public fieldStatic member ProgressStateProperty Identifies the ProgressState dependency property.
Public fieldStatic member ProgressValueProperty Identifies the ProgressValue dependency property.
Public fieldStatic member TaskbarItemInfoProperty Identifies the TaskbarItemInfo dependency property.
Public fieldStatic member ThumbButtonInfosProperty Identifies the ThumbButtonInfos dependency property.
Public fieldStatic member ThumbnailClipMarginProperty Identifies the ThumbnailClipMargin dependency property.

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Remarks

The TaskbarItemInfo class provides a managed wrapper for Windows 7 taskbar functionality. For more information about the Windows shell and native taskbar APIs, see Taskbar Extensions.

The Windows 7 taskbar provides enhanced functionality that enables you to use the taskbar item to communicate status to a user and expose common tasks when the window is minimized or hidden. The functionality that is exposed by the TaskbarItemInfo class is unavailable in versions of Windows earlier than Windows 7. Applications that use the TaskbarItemInfo class can still run in earlier versions of Windows; however, these taskbar enhancements are unavailable in the earlier versions. 

In Windows 7, some taskbar functionality might be unavailable, depending on the user's settings. For example, taskbar functionality is unavailable if Windows Aero is disabled or if the application is started with elevated permissions. Your application should provide other ways to interact with the user that do not depend on the enhanced taskbar functionality in Windows 7.

Program icons in the notification area, which is at the far right of the taskbar, are typically used to communicate application status to a user. By default, the Windows 7 taskbar hides program icons in the notification area. However, you can set the Overlay property to add an image to the taskbar button to communicate status, such as online status in a messaging application. The overlay image lets users see the application status even if they cannot see the program icon in the notification area. You can also display the progress of running tasks in the taskbar button by setting the ProgressState and ProgressValue properties.

The Windows 7 taskbar displays a thumbnail of the application when you move the mouse pointer over the taskbar button. By default the whole application window is shown. You can specify a particular part of the window to display in the thumbnail by setting the ThumbnailClipMargin property. You can also specify a Description that is displayed in a tooltip above the taskbar thumbnail. The tooltip is displayed even when the thumbnail cannot be seen because of user settings. 

You can add buttons to the taskbar thumbnail to provide access to common tasks without switching to the application window. For example, Window Media Player provides Play, Pause, Forward, and Back buttons that let you control media playback from the taskbar thumbnail when the application is minimized. Buttons in the taskbar thumbnail are represented by ThumbButtonInfo objects and are contained in the ThumbButtonInfos collection.

The following illustration shows the enhanced features of the Windows 7 taskbar.

Windows Taskbar Enhanced Features

Taskbar Item Info Sample

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.Shell Namespace