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Binding Class

Provides high-level access to the definition of a binding, which connects the properties of binding target objects (typically, WPF elements), and any data source (for example, a database, an XML file, or any object that contains data).

Namespace:  System.Windows.Data
Assembly:  PresentationFramework (in PresentationFramework.dll)
XMLNS for XAML: http://schemas.microsoft.com/winfx/2006/xaml/presentation, http://schemas.microsoft.com/netfx/2007/xaml/presentation

public class Binding : BindingBase
<object property="{Binding declaration}"/>

XAML Values


Zero or more attribute-assignment clauses separated by commas (,). For more information, see Binding Markup Extension or Binding Declarations Overview.

The Binding type exposes the following members.

Public methodBinding()Initializes a new instance of the Binding class.
Public methodBinding(String)Initializes a new instance of the Binding class with an initial path.

Public propertyAsyncStateInfrastructure. Gets or sets opaque data passed to the asynchronous data dispatcher.
Public propertyBindingGroupNameGets or sets the name of the BindingGroup to which this binding belongs. (Inherited from BindingBase.)
Public propertyBindsDirectlyToSourceGets or sets a value that indicates whether to evaluate the Path relative to the data item or the DataSourceProvider object.
Public propertyConverterGets or sets the converter to use.
Public propertyConverterCultureGets or sets the culture in which to evaluate the converter.
Public propertyConverterParameterGets or sets the parameter to pass to the Converter.
Public propertyElementNameGets or sets the name of the element to use as the binding source object.
Public propertyFallbackValueGets or sets the value to use when the binding is unable to return a value. (Inherited from BindingBase.)
Public propertyIsAsyncGets or sets a value that indicates whether the Binding should get and set values asynchronously.
Public propertyModeGets or sets a value that indicates the direction of the data flow in the binding.
Public propertyNotifyOnSourceUpdatedGets or sets a value that indicates whether to raise the SourceUpdated event when a value is transferred from the binding target to the binding source.
Public propertyNotifyOnTargetUpdatedGets or sets a value that indicates whether to raise the TargetUpdated event when a value is transferred from the binding source to the binding target.
Public propertyNotifyOnValidationErrorGets or sets a value that indicates whether to raise the Error attached event on the bound object.
Public propertyPathGets or sets the path to the binding source property.
Public propertyRelativeSourceGets or sets the binding source by specifying its location relative to the position of the binding target.
Public propertySourceGets or sets the object to use as the binding source.
Public propertyStringFormatGets or sets a string that specifies how to format the binding if it displays the bound value as a string. (Inherited from BindingBase.)
Public propertyTargetNullValueGets or sets the value that is used in the target when the value of the source is null. (Inherited from BindingBase.)
Public propertyUpdateSourceExceptionFilterGets or sets a handler you can use to provide custom logic for handling exceptions that the binding engine encounters during the update of the binding source value. This is only applicable if you have associated an ExceptionValidationRule with your binding.
Public propertyUpdateSourceTriggerGets or sets a value that determines the timing of binding source updates.
Public propertyValidatesOnDataErrorsGets or sets a value that indicates whether to include the DataErrorValidationRule.
Public propertyValidatesOnExceptionsGets or sets a value that indicates whether to include the ExceptionValidationRule.
Public propertyValidationRulesGets a collection of rules that check the validity of the user input.
Public propertyXPathGets or sets an XPath query that returns the value on the XML binding source to use.

Public attached propertyXmlNamespaceManagerGets or sets the XmlNamespaceManager used to perform namespace-aware XPath queries in XML bindings.

Public methodStatic memberAddSourceUpdatedHandlerAdds a handler for the SourceUpdated attached event.
Public methodStatic memberAddTargetUpdatedHandlerAdds a handler for the TargetUpdated attached event.
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 it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodStatic memberGetXmlNamespaceManagerReturns an XML namespace manager object used by the binding attached to the specified object.
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodProvideValueReturns an object that should be set on the property where this binding and extension are applied. (Inherited from BindingBase.)
Public methodStatic memberRemoveSourceUpdatedHandlerRemoves a handler for the SourceUpdated attached event.
Public methodStatic memberRemoveTargetUpdatedHandlerRemoves a handler for the TargetUpdated attached event.
Public methodStatic memberSetXmlNamespaceManagerSets a namespace manager object used by the binding attached to the provided element.
Public methodShouldSerializeFallbackValueReturns a value that indicates whether serialization processes should serialize the effective value of the FallbackValue property on instances of this class. (Inherited from BindingBase.)
Public methodShouldSerializePathIndicates whether the Path property should be persisted.
Public methodShouldSerializeSourceIndicates whether the Source property should be persisted.
Public methodShouldSerializeTargetNullValueReturns a value that indicates whether the TargetNullValue property should be serialized. (Inherited from BindingBase.)
Public methodShouldSerializeValidationRulesIndicates whether the ValidationRules property should be persisted.
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)

Public attached eventSourceUpdatedOccurs when a value is transferred from the binding target to the binding source, but only for bindings with the NotifyOnSourceUpdated value set to true.
Public attached eventTargetUpdatedOccurs when a value is transferred from the binding source to the binding target, but only for bindings with the NotifyOnTargetUpdated value set to true.

Public fieldStatic memberDoNothingUsed as a returned value to instruct the binding engine not to perform any action.
Public fieldStatic memberIndexerNameUsed as the PropertyName of System.ComponentModel.PropertyChangedEventArgs to indicate that an indexer property has changed.
Public fieldStatic memberSourceUpdatedEventIdentifies the SourceUpdated attached event.
Public fieldStatic memberTargetUpdatedEventIdentifies the TargetUpdated attached event.
Public fieldStatic memberXmlNamespaceManagerPropertyIdentifies the XmlNamespaceManager attached property.

Windows Presentation Foundation (WPF) data binding provides a simple and consistent way for applications to present and interact with data. Data binding enables you to synchronize the values of the properties of two different objects.

To establish a binding, use the Binding class or one of the other classes that inherit BindingBase. Regardless of what object you are binding and the nature of your data source, each binding follows the model illustrated by the following figure.

Basic data binding diagram

The figure demonstrates the following fundamental WPF data binding concepts.

  • Each binding typically has these four components: a binding target object, a target property, a binding source, and a Path to the value in the binding source to use. For example, if you want to bind the content of a TextBox to the Name property of an Employee object, your target object is the TextBox, the target property is the Text property, the value to use is Name, and the source object is the Employee object.

  • The target property must be a dependency property. This also means that you cannot bind a field. Most properties of UIElement objects are dependency properties and most dependency properties, except read-only ones, support data binding by default. (Only DependencyObject types can define dependency properties and all UIElement objects derive from DependencyObject.)

  • Although not specified in the figure, it should be noted that the binding source object is not restricted to being a custom CLR object. WPF data binding supports data in the form of CLR objects and XML. To provide some examples, your binding source may be a UIElement, any list object, a CLR object that is associated with ADO.NET data or Web Services, or an XmlNode that contains your XML data.

Use the Mode property to specify the direction of the data flow. To detect source changes in one-way or two-way bindings, the source must implement a suitable property change notification mechanism such as INotifyPropertyChanged. For an example, see How to: Implement Property Change Notification. The UpdateSourceTrigger property specifies the timing of source updates. For more information, see "Basic Data Binding Concepts" in Data Binding Overview.

This example shows you how to create a simple Binding.

In this example, you have a Person object with a string property named PersonName. The Person object is defined in the namespace called SDKSample.

The following example instantiates the Person object with a PersonName property value of Joe. This is done in the Resources section and assigned an x:Key.

  Title="Simple Data Binding Sample">

    <src:Person x:Key="myDataSource" PersonName="Joe"/>





To bind to the PersonName property you would do the following:

<TextBlock Text="{Binding Source={StaticResource myDataSource}, Path=PersonName}"/>

As a result, the TextBlock appears with the value "Joe".

More Code

How to: Specify the Binding SourceIn data binding, the binding source object refers to the object you obtain your data from. This topic describes the different ways of specifying the binding source.
How to: Create a Binding in CodeThis example shows how to create and set a Binding in code.
How to: Bind to XML Data Using an XMLDataProvider and XPath QueriesThis example shows how to bind to XML data using an XmlDataProvider.
How to: Implement Property Change NotificationTo support OneWay or TwoWay binding to enable your binding target properties to automatically reflect the dynamic changes of the binding source (for example, to have the preview pane updated automatically when the user edits a form), your class needs to provide the proper property changed notifications. This example shows how to create a class that implements INotifyPropertyChanged.
How to: Specify the Direction of the BindingThis example shows how to specify whether the binding updates only the binding target (target) property, the binding source (source) property, or both the target property and the source property.
How to: Control When the TextBox Text Updates the SourceThis topic describes how to use the UpdateSourceTrigger property to control the timing of binding source updates. The topic uses the TextBox control as an example.
How to: Bind to an ADO.NET Data SourceThis example shows how to bind a Windows Presentation Foundation (WPF) ListBox control to an ADO.NET DataSet.
How to: Sort Data in a ViewThis example describes how to sort data in a view.
How to: Filter Data in a ViewThis example shows how to filter data in a view.
How to: Bind to an EnumerationThis example shows how to bind to an enumeration by binding to the enumeration's GetValues method.

.NET Framework

Supported in: 4, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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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