在我的應用檢索BindingGroup代碼

Question

我使用MultiBinding綁定到一個XmlDataProvider一個TextBox：

<TextBox Name="TextBox_BaseId" 
     Grid.Row="0" 
     Grid.Column="1" 
     MaxLength="8" 
     Style="{StaticResource textBoxInError}"> 

    <i:Interaction.Behaviors> 
    <behaviors:DelayedUpdate /> 
    </i:Interaction.Behaviors> 

    <TextBox.Text> 
    <MultiBinding Converter="{StaticResource BaseIDConverter}" 
        UpdateSourceTrigger="Explicit"> 
     <Binding Source="{StaticResource dataProvider}" XPath="BLOCK[@id=1]/ITEMS/ITEM[(@id=12) and (@index=0)]/@value"/> 
     <Binding Source="{StaticResource dataProvider}" XPath="BLOCK[@id=1]/ITEMS/ITEM[(@id=12) and (@index=1)]/@value"/> 
     <Binding Source="{StaticResource dataProvider}" XPath="BLOCK[@id=1]/ITEMS/ITEM[(@id=12) and (@index=2)]/@value"/> 
     <Binding Source="{StaticResource dataProvider}" XPath="BLOCK[@id=1]/ITEMS/ITEM[(@id=12) and (@index=3)]/@value"/> 
     <MultiBinding.ValidationRules> 
     <local:RangeValidator Min="1" Max="16215777" /> 
     </MultiBinding.ValidationRules> 
    </MultiBinding> 
    </TextBox.Text> 
</TextBox> 

現在，因爲我想手動控制更新源，我創建了一個行爲類「延遲」了更新：

public class DelayedUpdate : Behavior<TextBox> 
{ 
    Timer _timer = new Timer(1000); 

    protected override void OnAttached() 
    { 
    base.OnAttached(); 
    AssociatedObject.KeyUp += AssociatedObject_KeyUp;  
    _timer.Elapsed += _timer_Elapsed; 
    } 

    protected override void OnDetaching() 
    { 
    base.OnDetaching(); 
    AssociatedObject.KeyUp -= AssociatedObject_KeyUp; 
    _timer.Elapsed -= _timer_Elapsed; 
    } 

    void _timer_Elapsed(object sender, ElapsedEventArgs e) 
    { 
    _timer.Enabled = false; 

    Application.Current.Dispatcher.BeginInvoke((Action)(() => 
    { 
     AssociatedObject.BindingGroup.CommitEdit(); 
    }), 
    System.Windows.Threading.DispatcherPriority.Normal);  
    } 

    void AssociatedObject_KeyUp(object sender, KeyEventArgs e) 
    { 
    _timer.Enabled = true; 
    } 

} 

但是，當定時器引發AssociatedObject.BindingGroup返回NULL。 有人能告訴我我錯在哪裏，或者如果有最好的方法來做到這一點？

Regards，
Daniele。

Answer 1

BindingGroup和MultiBinding是兩個完全不同的東西。如果你想明確提交一個綁定，你可以使用：

BindingOperations.GetMultiBindingExpression(AssociatedObject, TextBox.TextProperty) 
    .UpdateSource();