BindingExpression Class

BindingExpression Class

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

Contains information about a single binding within a Binding object.


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

public sealed class BindingExpression : BindingExpressionBase

The BindingExpression type exposes the following members.

Public propertyDataItemGets the binding source object that this BindingExpression uses.
Public propertyParentBindingReturns the Binding object of the current BindingExpression.

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 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 bindings.

A Binding object can be used by multiple binding targets. The BindingExpression class, however, represents a single binding. You can retrieve a BindingExpression instance from a binding target by calling its FrameworkElement.GetBindingExpression method. You can then use the BindingExpression to call the UpdateSource method. This is useful to control when values are copied from the binding target to the binding source. For more information, see Data binding for Windows Phone 8.

The following code example demonstrates how to use this method.

<TextBox x:Name="textBox1" Text="{Binding Test, Mode=TwoWay, UpdateSourceTrigger=Explicit}" />
<Button Content="Update" Click="Button_Click" />

public class TestData
    public String Test { get; set; }

TestData data;

public MainPage()
    data = new TestData { Test = "one" };
    textBox1.DataContext = data;

private void Button_Click(object sender, RoutedEventArgs e)
    BindingExpression expression = textBox1.GetBindingExpression(TextBox.TextProperty);
    MessageBox.Show("Before UpdateSource, Test = " + data.Test);
    MessageBox.Show("After UpdateSource, Test = " + data.Test);

Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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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