BindingExpression Class

Contains information about a single instance of a Binding.

Namespace:  System.Windows.Data
Assembly:  PresentationFramework (in PresentationFramework.dll)

public ref class BindingExpression sealed : public BindingExpressionBase, 
	IWeakEventListener

The BindingExpression type exposes the following members.

  NameDescription
Public propertyDataItemGets the binding source object that this BindingExpression uses.
Public propertyHasErrorGets a value that indicates whether the parent binding has a failed validation rule. (Inherited from BindingExpressionBase.)
Public propertyParentBindingReturns the Binding object of the current BindingExpression.
Public propertyParentBindingBaseGets the BindingBase object from which this BindingExpressionBase object is created. (Inherited from BindingExpressionBase.)
Public propertyStatusGets the status of the binding expression. (Inherited from BindingExpressionBase.)
Public propertyValidationErrorGets the ValidationError that caused this instance of BindingExpressionBase to be invalid. (Inherited from BindingExpressionBase.)
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  NameDescription
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.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
Public methodUpdateSourceSends the current binding target value to the binding source property in TwoWay or OneWayToSource bindings. (Overrides BindingExpressionBase::UpdateSource().)
Public methodUpdateTargetForces a data transfer from the binding source property to the binding target property. (Overrides BindingExpressionBase::UpdateTarget().)
Public methodValidateWithoutUpdateRuns any ValidationRule objects on the associated Binding that have the ValidationStep property set to RawProposedValue or ConvertedProposedValue. This method does not update the source. (Inherited from BindingExpressionBase.)
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  NameDescription
Explicit interface implemetationPrivate methodIWeakEventListener::ReceiveWeakEventThis member supports the Windows Presentation Foundation (WPF) infrastructure and is not intended to be used directly from your code.
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The Binding class is the high-level class for the declaration of a binding. The BindingExpression class is the underlying object that maintains the connection between the binding source and the binding target. A Binding contains all the information that can be shared across several BindingExpression objects. A BindingExpression is an instance expression that cannot be shared and that contains all the instance information about the Binding.

For example, consider the following, where myDataObject is an instance of the MyData class, myBinding is the source Binding object, and MyData class is a defined class that contains a string property named MyDataProperty. This example binds the text content of mytext, which is an instance of TextBlock, to MyDataProperty.

No code example is currently available or this language may not be supported.

You can use the same myBinding object to create other bindings. For example, you might use the myBinding object to bind the text content of a check box to MyDataProperty. In that scenario, there will be two instances of BindingExpression that share the myBinding object.

You can obtain a BindingExpression object by using the GetBindingExpression method or the GetBindingExpression method on a data-bound object.

This example shows how to obtain the binding object from a data-bound target property.

You can do the following to get the Binding object:


// textBox3 is an instance of a TextBox
// the TextProperty is the data-bound dependency property
Binding myBinding = BindingOperations.GetBinding(textBox3, TextBox.TextProperty);


NoteNote

You must specify the dependency property for the binding you want because it is possible that more than one property of the target object is using data binding.

Alternatively, you can get the BindingExpression and then get the value of the ParentBinding property.

For the complete example see Binding Validation Sample.

NoteNote

If your binding is a MultiBinding, use BindingOperations.GetMultiBinding. If it is a PriorityBinding, use BindingOperations.GetPriorityBinding. If you are uncertain whether the target property is bound using a Binding, a MultiBinding, or a PriorityBinding, you can use BindingOperations.GetBindingBase.

.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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