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Label Class

Displays a caption, required field indicator, and validation error indicator for an associated control.

Namespace:  System.Windows.Controls
Assembly:  System.Windows.Controls.Data.Input (in System.Windows.Controls.Data.Input.dll)
[TemplateVisualStateAttribute(Name = "Invalid", GroupName = "ValidationStates")]
[TemplateVisualStateAttribute(Name = "Disabled", GroupName = "CommonStates")]
[TemplateVisualStateAttribute(Name = "Normal", GroupName = "CommonStates")]
[TemplateVisualStateAttribute(Name = "Valid", GroupName = "ValidationStates")]
[TemplateVisualStateAttribute(Name = "NotRequired", GroupName = "RequiredStates")]
[TemplateVisualStateAttribute(Name = "Required", GroupName = "RequiredStates")]
public class Label : ContentControl
<sdk:Label .../>
-or-
<sdk:Label>
  singleObject
</sdk:Label>
-or-
<sdk:Label>stringContent</sdk:Label>

XAML Values

singleObject

A single object element that declares the content.

stringContent

A string that is displayed as content through the default template ContentPresenter. For more information, see "String Content of a ContentControl" section of ContentControl.

The Label type exposes the following members.

  NameDescription
Public methodLabelInitializes a new instance of the Label class.
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  NameDescription
Public propertyActualHeightGets the rendered height of a FrameworkElement. (Inherited from FrameworkElement.)
Public propertyActualWidthGets the rendered width of a FrameworkElement. (Inherited from FrameworkElement.)
Public propertyAllowDropGets or sets a value that determines whether this UIElement can be a drop target for purposes of Silverlight drag-and-drop operations. (Inherited from UIElement.)
Public propertyBackgroundGets or sets a brush that provides the background of the control. (Inherited from Control.)
Public propertyBorderBrushGets or sets a brush that describes the border background of a control. (Inherited from Control.)
Public propertyBorderThicknessGets or sets the border thickness of a control. (Inherited from Control.)
Public propertyCacheModeGets or sets a value that indicates that rendered content should be cached when possible. (Inherited from UIElement.)
Public propertyCharacterSpacingGets or sets the distance between characters of text in the control measured in 1000ths of the font size. (Inherited from Control.)
Public propertyClipGets or sets the Geometry used to define the outline of the contents of a UIElement. (Inherited from UIElement.)
Public propertyContentGets or sets the value of the ContentControl dependency property. (Inherited from ContentControl.)
Public propertyContentTemplateGets or sets the data template that is used to display the content of the ContentControl. (Inherited from ContentControl.)
Public propertyCursorGets or sets the cursor image that displays while the mouse pointer is over a FrameworkElement. (Inherited from FrameworkElement.)
Public propertyDataContextGets or sets the data context for a FrameworkElement when it participates in data binding. (Inherited from FrameworkElement.)
Protected propertyDefaultStyleKeyGets or sets the key that references the default style for the control. (Inherited from Control.)
Public propertyDesiredSizeGets the size that this UIElement computed during the measure pass of the layout process. (Inherited from UIElement.)
Public propertyDispatcherGets the Dispatcher this object is associated with. (Inherited from DependencyObject.)
Public propertyEffectGets or sets the pixel shader effect to use for rendering this UIElement. (Inherited from UIElement.)
Public propertyFlowDirectionGets or sets the direction that text and other user interface elements flow within any parent element that controls their layout. (Inherited from FrameworkElement.)
Public propertyFontFamilyGets or sets the font used to display text in the control. (Inherited from Control.)
Public propertyFontSizeGets or sets the size of the text in this control. (Inherited from Control.)
Public propertyFontStretchGets or sets the degree to which a font is condensed or expanded on the screen. (Inherited from Control.)
Public propertyFontStyleGets or sets the style in which the text is rendered. (Inherited from Control.)
Public propertyFontWeightGets or sets the thickness of the specified font. (Inherited from Control.)
Public propertyForegroundGets or sets a brush that describes the foreground color. (Inherited from Control.)
Public propertyHeightGets or sets the suggested height of a FrameworkElement. (Inherited from FrameworkElement.)
Public propertyHorizontalAlignmentGets or sets the horizontal alignment characteristics that are applied to a FrameworkElement when it is composed in a layout parent, such as a panel or items control. (Inherited from FrameworkElement.)
Public propertyHorizontalContentAlignmentGets or sets the horizontal alignment of the control's content. (Inherited from Control.)
Public propertyIsEnabledGets or sets a value indicating whether the user can interact with the control. (Inherited from Control.)
Public propertyIsHitTestVisibleGets or sets whether the contained area of this UIElement can return true values for hit testing. (Inherited from UIElement.)
Public propertyIsRequiredGets or sets a value that indicates whether the property bound to the Target field is required.
Public propertyIsTabStopGets or sets a value that indicates whether a control is included in tab navigation. (Inherited from Control.)
Public propertyIsValidGets a value that indicates whether the Target field data is valid.
Public propertyLanguageGets or sets localization/globalization language information that applies to a FrameworkElement. (Inherited from FrameworkElement.)
Public propertyMarginGets or sets the outer margin of a FrameworkElement. (Inherited from FrameworkElement.)
Public propertyMaxHeightGets or sets the maximum height constraint of a FrameworkElement. (Inherited from FrameworkElement.)
Public propertyMaxWidthGets or sets the maximum width constraint of a FrameworkElement. (Inherited from FrameworkElement.)
Public propertyMinHeightGets or sets the minimum height constraint of a FrameworkElement. (Inherited from FrameworkElement.)
Public propertyMinWidthGets or sets the minimum width constraint of a FrameworkElement. (Inherited from FrameworkElement.)
Public propertyNameGets or sets the identifying name of the object. When a XAML processor creates the object tree from XAML markup, run-time code can refer to the XAML-declared object by this name. (Inherited from FrameworkElement.)
Public propertyOpacityGets or sets the degree of the object's opacity. (Inherited from UIElement.)
Public propertyOpacityMaskGets or sets the brush used to alter the opacity of regions of this object. (Inherited from UIElement.)
Public propertyPaddingGets or sets the padding inside a control. (Inherited from Control.)
Public propertyParentGets the parent object of this FrameworkElement in the object tree. (Inherited from FrameworkElement.)
Public propertyProjectionGets or sets the perspective projection (3-D effect) to apply when rendering this UIElement. (Inherited from UIElement.)
Public propertyPropertyPathGets or sets the path to the dependency property on the DataContext of the Target control that this Label is associated with.
Public propertyRenderSizeGets the final render size of a UIElement. (Inherited from UIElement.)
Public propertyRenderTransformGets or sets transform information that affects the rendering position of a UIElement. (Inherited from UIElement.)
Public propertyRenderTransformOriginGets or sets the origin point of any possible render transform declared by RenderTransform, relative to the bounds of the UIElement. (Inherited from UIElement.)
Public propertyResourcesGets the locally defined resource dictionary. In XAML, you can establish resource items as child object elements of a frameworkElement.Resources property element, through XAML implicit collection syntax. (Inherited from FrameworkElement.)
Public propertyStyleGets or sets an instance Style that is applied for this object during rendering. (Inherited from FrameworkElement.)
Public propertyTabIndexGets or sets a value that determines the order in which elements receive focus when the user navigates through controls by using the TAB key. (Inherited from Control.)
Public propertyTabNavigationGets or sets a value that modifies how tabbing and TabIndex work for this control. (Inherited from Control.)
Public propertyTagGets or sets an arbitrary object value that can be used to store custom information about this object. (Inherited from FrameworkElement.)
Public propertyTargetGets or sets the control that this Label is associated with.
Public propertyTemplateGets or sets a control template. (Inherited from Control.)
Public propertyTriggersGets the collection of triggers for animations that are defined for a FrameworkElement. (Inherited from FrameworkElement.)
Public propertyUseLayoutRoundingGets or sets a value that determines whether rendering for the object and its visual subtree should use rounding behavior that aligns rendering to whole pixels. (Inherited from UIElement.)
Public propertyVerticalAlignmentGets or sets the vertical alignment characteristics that are applied to a FrameworkElement when it is composed in a parent object such as a panel or items control. (Inherited from FrameworkElement.)
Public propertyVerticalContentAlignmentGets or sets the vertical alignment of the control's content. (Inherited from Control.)
Public propertyVisibilityGets or sets the visibility of a UIElement. A UIElement that is not visible does not render and does not communicate its desired size to layout. (Inherited from UIElement.)
Public propertyWidthGets or sets the width of a FrameworkElement. (Inherited from FrameworkElement.)
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  NameDescription
Public methodAddHandlerAdds a routed event handler for a specified routed event, adding the handler to the handler collection on the current element. Specify handledEventsToo as true to have the provided handler be invoked for routed event that had already been marked as handled by another element along the event route. (Inherited from UIElement.)
Public methodApplyTemplateLoads the relevant control template so that its parts can be referenced. (Inherited from Control.)
Public methodArrangePositions child objects and determines a size for a UIElement. Parent objects that implement custom layout for their child elements should call this method from their layout override implementations to form a recursive layout update. (Inherited from UIElement.)
Protected methodArrangeOverrideProvides the behavior for the Arrange pass of Silverlight layout. Classes can override this method to define their own Arrange pass behavior. (Inherited from FrameworkElement.)
Public methodCaptureMouseSets mouse capture to a UIElement. (Inherited from UIElement.)
Public methodCheckAccessDetermines whether the calling thread has access to this object. (Inherited from DependencyObject.)
Public methodClearValueClears the local value of a dependency property. (Inherited from DependencyObject.)
Public methodEquals(Object)Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
Public methodFindNameRetrieves an object that has the specified identifier name. (Inherited from FrameworkElement.)
Public methodFocusAttempts to set the focus on the control. (Inherited from Control.)
Public methodGetAnimationBaseValueReturns any base value established for a Silverlight dependency property, which would apply in cases where an animation is not active. (Inherited from DependencyObject.)
Public methodGetBindingExpressionRetrieves the BindingExpression for a dependency property where a binding is established. (Inherited from FrameworkElement.)
Public methodGetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Protected methodGetTemplateChildRetrieves the named element in the instantiated ControlTemplate visual tree. (Inherited from Control.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodGetValueReturns the current effective value of a dependency property from a DependencyObject. (Inherited from DependencyObject.)
Public methodInvalidateArrangeInvalidates the arrange state (layout) for a UIElement. After the invalidation, the UIElement will have its layout updated, which will occur asynchronously. (Inherited from UIElement.)
Public methodInvalidateMeasureInvalidates the measurement state (layout) for a UIElement. (Inherited from UIElement.)
Public methodMeasureUpdates the DesiredSize of a UIElement. Typically, objects that implement custom layout for their layout children call this method from their own MeasureOverride implementations to form a recursive layout update. (Inherited from UIElement.)
Protected methodMeasureOverrideProvides the behavior for the Measure pass of Silverlight layout. Classes can override this method to define their own Measure pass behavior. (Inherited from FrameworkElement.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodOnApplyTemplateBuilds the visual tree for the Label control when a new template is applied. (Overrides FrameworkElement.OnApplyTemplate().)
Protected methodOnContentChangedCalled when the value of the Content property changes. (Overrides ContentControl.OnContentChanged(Object, Object).)
Protected methodOnCreateAutomationPeerReturns a LabelAutomationPeer for use by the Silverlight automation infrastructure. (Overrides UIElement.OnCreateAutomationPeer().)
Protected methodOnDragEnterCalled before the DragEnter event occurs. (Inherited from Control.)
Protected methodOnDragLeaveCalled before the DragLeave event occurs. (Inherited from Control.)
Protected methodOnDragOverCalled before the DragOver event occurs. (Inherited from Control.)
Protected methodOnDropCalled before the Drop event occurs. (Inherited from Control.)
Protected methodOnGotFocusCalled before the GotFocus event occurs. (Inherited from Control.)
Protected methodOnKeyDownCalled before the KeyDown event occurs. (Inherited from Control.)
Protected methodOnKeyUpCalled before the KeyUp event occurs. (Inherited from Control.)
Protected methodOnLostFocusCalled before the LostFocus event occurs. (Inherited from Control.)
Protected methodOnLostMouseCaptureCalled before the LostMouseCapture event occurs to provide handling for the event in a derived class without attaching a delegate. (Inherited from Control.)
Protected methodOnMouseEnterCalled before the MouseEnter event occurs. (Inherited from Control.)
Protected methodOnMouseLeaveCalled before the MouseLeave event occurs. (Inherited from Control.)
Protected methodOnMouseLeftButtonDownCalled before the MouseLeftButtonDown event occurs. (Inherited from Control.)
Protected methodOnMouseLeftButtonUpCalled before the MouseLeftButtonUp event occurs. (Inherited from Control.)
Protected methodOnMouseMoveCalled before the MouseMove event occurs. (Inherited from Control.)
Protected methodOnMouseRightButtonDownCalled before the MouseRightButtonDown event occurs. (Inherited from Control.)
Protected methodOnMouseRightButtonUpCalled before the MouseRightButtonUp event occurs. (Inherited from Control.)
Protected methodOnMouseWheelCalled before the MouseWheel event occurs to provide handling for the event in a derived class without attaching a delegate. (Inherited from Control.)
Protected methodOnTextInputCalled before the TextInput event occurs. (Inherited from Control.)
Protected methodOnTextInputStartCalled before the TextInputStart event occurs. (Inherited from Control.)
Protected methodOnTextInputUpdateCalled before the TextInputUpdate event occurs. (Inherited from Control.)
Public methodReadLocalValueReturns the local value of a dependency property, if a local value is set. (Inherited from DependencyObject.)
Public methodRefreshReloads the metadata from the Target element.
Public methodReleaseMouseCaptureRemoves mouse capture from a UIElement. After this call, typically no object holds mouse capture. (Inherited from UIElement.)
Public methodRemoveHandlerRemoves the specified routed event handler from this UIElement. (Inherited from UIElement.)
Public methodSetBindingAttaches a binding to a FrameworkElement, using the provided binding object, and returns a BindingExpressionBase for possible later use. (Inherited from FrameworkElement.)
Public methodSetValueSets the local value of a dependency property on a DependencyObject. (Inherited from DependencyObject.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
Public methodTransformToVisualReturns a transform object that can be used to transform coordinates from the UIElement to the specified object. (Inherited from UIElement.)
Public methodUpdateLayoutEnsures that all positions of child objects of a UIElement are properly updated for layout. (Inherited from UIElement.)
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  NameDescription
Public eventBindingValidationErrorOccurs when a data validation error is reported by a binding source. (Inherited from FrameworkElement.)
Public eventDataContextChangedOccurs when the data context for this element changes. (Inherited from FrameworkElement.)
Public eventDragEnterOccurs when the input system reports an underlying drag event with this element as the target. (Inherited from UIElement.)
Public eventDragLeaveOccurs when the input system reports an underlying drag event with this element as the origin. (Inherited from UIElement.)
Public eventDragOverOccurs when the input system reports an underlying drag event with this element as the potential drop target. (Inherited from UIElement.)
Public eventDropOccurs when the input system reports an underlying drop event with this element as the drop target. (Inherited from UIElement.)
Public eventGotFocusOccurs when a UIElement receives focus. (Inherited from UIElement.)
Public eventIsEnabledChangedOccurs when the IsEnabled property changes. (Inherited from Control.)
Public eventKeyDownOccurs when a keyboard key is pressed while the UIElement has focus. (Inherited from UIElement.)
Public eventKeyUpOccurs when a keyboard key is released while the UIElement has focus. (Inherited from UIElement.)
Public eventLayoutUpdatedOccurs when the layout of the Silverlight visual tree changes. (Inherited from FrameworkElement.)
Public eventLoadedOccurs when a FrameworkElement has been constructed and added to the object tree. (Inherited from FrameworkElement.)
Public eventLostFocusOccurs when a UIElement loses focus. (Inherited from UIElement.)
Public eventLostMouseCaptureOccurs when the UIElement loses mouse capture. (Inherited from UIElement.)
Public eventMediaCommandOccurs when a button is pressed on a remote control. (Inherited from UIElement.)
Public eventMouseEnterOccurs when the mouse (or a stylus) enters the bounding area of a UIElement. (Inherited from UIElement.)
Public eventMouseLeaveOccurs when the mouse (or the stylus) leaves the bounding area of a UIElement. (Inherited from UIElement.)
Public eventMouseLeftButtonDownOccurs when the left mouse button is pressed (or when the tip of the stylus touches the tablet) while the mouse pointer is over a UIElement. (Inherited from UIElement.)
Public eventMouseLeftButtonUpOccurs when the left mouse button is released (or the tip of the stylus is removed from the tablet) while the mouse (or the stylus) is over a UIElement (or while a UIElement holds mouse capture). (Inherited from UIElement.)
Public eventMouseMoveOccurs when the coordinate position of the mouse (or stylus) changes while over a UIElement (or while a UIElement holds mouse capture). (Inherited from UIElement.)
Public eventMouseRightButtonDownOccurs when the right mouse button is pressed while the mouse pointer is over a UIElement. (Inherited from UIElement.)
Public eventMouseRightButtonUpOccurs when the right mouse button is released while the mouse pointer is over a UIElement. However, this event will only be raised if a caller marks the preceding MouseRightButtonDown event as handled; see Remarks. (Inherited from UIElement.)
Public eventMouseWheelOccurs when the user rotates the mouse wheel while the mouse pointer is over a UIElement, or the UIElement has focus. (Inherited from UIElement.)
Public eventSizeChangedOccurs when either the ActualHeight or the ActualWidth properties change value on a FrameworkElement. (Inherited from FrameworkElement.)
Public eventTextInputOccurs when a UI element gets text in a device-independent manner. (Inherited from UIElement.)
Public eventTextInputStartOccurs when a UI element initially gets text in a device-independent manner. (Inherited from UIElement.)
Public eventTextInputUpdateOccurs when text continues to be composed via an input method editor (IME). (Inherited from UIElement.)
Public eventUnloadedOccurs when this object is no longer connected to the main object tree. (Inherited from FrameworkElement.)
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  NameDescription
Public fieldStatic memberIsRequiredPropertyIdentifies the IsRequired dependency property.
Public fieldStatic memberIsValidPropertyIdentifies the IsValid dependency property.
Public fieldStatic memberPropertyPathPropertyIdentifies the PropertyPath dependency property.
Public fieldStatic memberTargetPropertyIdentifies the Target dependency property.
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A Label control displays a caption, required field indicator, and validation error indicator to the user. It is typically used together with an input control, such as a TextBox. If you do not need to display required field or validation indicators, you can use the TextBlock control instead.

To associate a Label with another control, you set the Target property of the Label. The Target is a reference to a UIElement. You can set the Target in code or through an ElementName binding in XAML.

When the Target property is set, a Label inspects each DependencyProperty on the Target control for a Binding. For each Binding that is found, it inspects the Source of the Binding for metadata. The metadata can be used to set the caption text, specify whether the field is required, and specify validation rules. If the Target control has more than one Binding, you can specify the one to retrieve metadata from by setting the PropertyPath property.

You use the Content property to set the caption of a Label. For more information about the content model for Label, see Control Content Models. If the property associated with the Label has a DisplayAttribute and the Name property is not null or an empty string, the Content will be set to the value of the DisplayAttribute.Name property. For more information, see Using Data Annotations to Customize Data Classes.

By default, the Label control indicates a required field by making the caption text bold. You put the Label in the Required visual state by setting the IsRequired property to true, or by putting a RequiredAttribute on the property the Label is associated with.

By default, the Label control indicates a validation error by making the caption text red. When the Target property is set, a Label responds to the BindingValidationError event for the Target control. It changes to its Invalid visual state when an error occurs, and to its Valid visual state when the error is resolved. In order to receive error notifications, you must set the ValidatesOnExceptions and NotifyOnValidationError properties on the Target controls Binding to true.

NoteNote:

The Label control in Silverlight does not provide support for access keys.

NoteNote:

The Label control is available as part of the libraries in the Silverlight Software Development Kit (SDK). For more information, see the Silverlight Tools.

Customizing the Label Control

To apply the same property settings to multiple Label controls, use the Style property. To change the visual structure and visual behavior of a Label, copy and modify its default style and template. For more information, see Control Customization.

Dependency properties for this control might be set by the default style of the control. If a dependency property for a Label is set by its default style, the property might change from its default value when the Label appears in the application. For more information, see Dependency Property Value Precedence. You can get the default style and template for Label from Label Styles and Templates.

NoteNote:

Setting a visual property will only have an effect if that property is both present in Label control's default template and is set by using a TemplateBinding. You can find a list of visual properties in the "Changing the Visual Structure of a Control" section of Customizing the Appearance of an Existing Control by Using a ControlTemplate.

The following example demonstrates two Label controls on a form. The first Label is used unbound to identify a DatePicker control. The second Label is bound to a TextBox named tbIdNumber, which is bound to the IdNumber property of a Customer object. This example is part of a larger example available in the ValidationSummary class overview.

Run this sample


<!-- Unbound Date of Birth field -->
<sdk:Label Content="Date of Birth" IsRequired="True" Margin="5" />
<StackPanel Orientation="Horizontal" Grid.Column="1">
    <sdk:DatePicker Height="23" />
    <sdk:DescriptionViewer Description="Please enter your date of birth."/>
</StackPanel>

<!-- ID Number field -->
<sdk:Label Grid.Row="1" Margin="5" 
                 Target="{Binding ElementName=tbIdNumber}" />
<StackPanel Orientation="Horizontal" Grid.Column="1" Grid.Row="1">
    <TextBox x:Name="tbIdNumber" Height="23" Width="100"
             Text="{Binding IdNumber, Mode=TwoWay, 
                    ValidatesOnExceptions=true, NotifyOnValidationError=true}" />
    <sdk:DescriptionViewer Target="{Binding ElementName=tbIdNumber}"/>
</StackPanel>


Silverlight

Supported in: 5, 4, 3

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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