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BindingExpression.UpdateSource Method

Silverlight

Sends the current binding target value to the binding source property in TwoWay bindings.

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

'Declaration
Public Sub UpdateSource

Exceptions

Exception	Condition
InvalidOperationException	The BindingExpression is detached from the binding target.

Remarks

You can use this method to control when the data source is updated. This is useful, for example, to validate several controls together before you update their data sources.

Examples

The following code example demonstrates how to use this method.

XAML


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


Public Class TestData
    Private testValue As String
    Public Property Test() As String
        Get
            Return testValue
        End Get
        Set(ByVal value As String)
            testValue = value
        End Set
    End Property
End Class

Private data As TestData

Public Sub New()

    InitializeComponent()

    data = New TestData
    With data
        .Test = "one"
    End With

    textBox1.DataContext = data

End Sub

Private Sub Button_Click(ByVal sender As Object, _
    ByVal e As RoutedEventArgs)

    Dim expression As BindingExpression = _
        textBox1.GetBindingExpression(TextBox.TextProperty)
    MessageBox.Show("Before UpdateSource, Test = " & data.Test)
    expression.UpdateSource()
    MessageBox.Show("After UpdateSource, Test = " & data.Test)

End Sub