Silverlight 是否在运行时覆盖设置XAML属性?
当我使用以下代码行时,从Silverlight类库实现模板控件Silverlight 是否在运行时覆盖设置XAML属性?,silverlight,xaml,controls,dependency-properties,controltemplate,Silverlight,Xaml,Controls,Dependency Properties,Controltemplate,当我使用以下代码行时,从Silverlight类库实现模板控件 <Style TargetType="local:SliderControl"> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="local:SliderControl"> <Grid x:Name="L
<Style TargetType="local:SliderControl">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="local:SliderControl">
<Grid x:Name="LayoutRoot" Background="White">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<sdk:Label x:Name="lblLabel" Content="" HorizontalContentAlignment="Center" />
<Slider x:Name="sldValue" Grid.Row="1" Orientation="Vertical" />
<TextBox x:Name="txtValue" Grid.Row="2" MaxWidth="50" MinWidth="50" Text="{Binding ElementName=sldValue, Path=Value, StringFormat=\{0:N2\}}" />
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
[TemplatePart(Name = "sldValue", Type = typeof(Slider)), TemplatePart(Name = "lblLabel", Type = typeof(Label))]
public class SliderControl : Control
{
private Slider _sliderElement;
private Slider SliderElement
{
get { return _sliderElement; }
set {
if (_sliderElement != null)
_sliderElement.ValueChanged -= new RoutedPropertyChangedEventHandler<double>(sldValue_ValueChanged);;
_sliderElement = value;
if (_sliderElement != null)
_sliderElement.ValueChanged += new RoutedPropertyChangedEventHandler<double>(sldValue_ValueChanged);
}
}
public event EventHandler<ValueChangingEventArgs> ValueChanging;
public static readonly DependencyProperty ValueProperty =
DependencyProperty.Register("Value", typeof(double), typeof(SliderControl), new PropertyMetadata(0.0, ValuePropertyChanged));
private static void ValuePropertyChanged(DependencyObject obj, DependencyPropertyChangedEventArgs args)
{
if (obj is SliderControl)
{
SliderControl sliderUserControl = (SliderControl)obj;
if (sliderUserControl.SliderElement != null)
{
sliderUserControl.SliderElement.Value = (double)args.NewValue;
}
}
}
public SliderControl()
{
this.DefaultStyleKey = typeof(SliderControl);
}
private void sldValue_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e)
{
if (ValueChanging != null)
{
ValueChanging(this, new ValueChangingEventArgs(e.OldValue, e.NewValue));
}
}
public override void OnApplyTemplate()
{
SliderElement = GetTemplateChild("sldValue") as Slider;
base.OnApplyTemplate();
}
}
我在VS设计视图中看到滑块的值为4。但当我运行应用程序时,滑块从0开始。所以,当我在XAML中更改属性时,我可以看到更改,但我当然也希望在运行时将值设置为4。在这种情况下,DependencyProperty是否覆盖该值
下面是Silverlight类库中的模板控件
<Style TargetType="local:SliderControl">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="local:SliderControl">
<Grid x:Name="LayoutRoot" Background="White">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<sdk:Label x:Name="lblLabel" Content="" HorizontalContentAlignment="Center" />
<Slider x:Name="sldValue" Grid.Row="1" Orientation="Vertical" />
<TextBox x:Name="txtValue" Grid.Row="2" MaxWidth="50" MinWidth="50" Text="{Binding ElementName=sldValue, Path=Value, StringFormat=\{0:N2\}}" />
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
[TemplatePart(Name = "sldValue", Type = typeof(Slider)), TemplatePart(Name = "lblLabel", Type = typeof(Label))]
public class SliderControl : Control
{
private Slider _sliderElement;
private Slider SliderElement
{
get { return _sliderElement; }
set {
if (_sliderElement != null)
_sliderElement.ValueChanged -= new RoutedPropertyChangedEventHandler<double>(sldValue_ValueChanged);;
_sliderElement = value;
if (_sliderElement != null)
_sliderElement.ValueChanged += new RoutedPropertyChangedEventHandler<double>(sldValue_ValueChanged);
}
}
public event EventHandler<ValueChangingEventArgs> ValueChanging;
public static readonly DependencyProperty ValueProperty =
DependencyProperty.Register("Value", typeof(double), typeof(SliderControl), new PropertyMetadata(0.0, ValuePropertyChanged));
private static void ValuePropertyChanged(DependencyObject obj, DependencyPropertyChangedEventArgs args)
{
if (obj is SliderControl)
{
SliderControl sliderUserControl = (SliderControl)obj;
if (sliderUserControl.SliderElement != null)
{
sliderUserControl.SliderElement.Value = (double)args.NewValue;
}
}
}
public SliderControl()
{
this.DefaultStyleKey = typeof(SliderControl);
}
private void sldValue_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e)
{
if (ValueChanging != null)
{
ValueChanging(this, new ValueChangingEventArgs(e.OldValue, e.NewValue));
}
}
public override void OnApplyTemplate()
{
SliderElement = GetTemplateChild("sldValue") as Slider;
base.OnApplyTemplate();
}
}
我没有看到注册DependencyProperty时声明的Value属性 然后将属性绑定到构造函数中的控件:
public SliderControl(){
InitializeComponent();
this.sldValue.SetBinding(Slider.ValueProperty, new Binding()
{
Source = this,
Path = new PropertyPath("Value"),
Mode = BindingMode.TwoWay
});
}
我成功了!我只是把gmcalab的解决方案放在OnApplyTemplate中。 多亏了gmcalab
public override void OnApplyTemplate()
{
SliderElement = GetTemplateChild("sldValue") as Slider;
if (SliderElement != null)
{
SliderElement.SetBinding(Slider.ValueProperty, new Binding()
{
Source = this,
Path = new PropertyPath("Value"),
Mode = BindingMode.TwoWay
});
}
base.OnApplyTemplate();
}
谢谢你的快速回复。注册DependencyProperty时声明的Value属性未被错误地过帐。我道歉。我立即尝试了您有趣的解决方案,但我正在尝试使用模板控件。我假设,因为OnApplyTemplate尚未被调用,所以在我的模板控件中,我没有将滑块设置为子控件的引用。使用附加属性是个好主意,还是我也在考虑从silder继承整个模板控件并传递所有属性。我想一定有更好的解决办法。