[英]Bind to Control's Property inside VisualStateManager
I searched for this Problem on Stackoverflow, but in my opinion the other Posts do not cover this question. 我在Stackoverflow上搜索了这个问题,但在我看来,其他帖子没有涵盖这个问题。
In my Custom Control i am using a Visual State Manager. 在我的自定义控件中,我使用的是Visual State Manager。 Inside the Visual State Manager there is an Animation that Animates the Height of an Element.
在可视状态管理器内部有一个动画,可以动画元素的高度。 When i try to bind to the Controls Properties i get following Error on StartUp:
当我尝试绑定到控件属性时,我在启动时遇到以下错误:
Additional information: Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType=MyNameSpace.MyControl, AncestorLevel='1''.
附加信息:找不到引用'RelativeSource FindAncestor,AncestorType = MyNameSpace.MyControl,AncestorLevel ='1'的绑定源。 BindingExpression:Path=ActualHeight;
BindingExpression:路径=的ActualHeight; DataItem=null;
的DataItem = NULL; target element is 'DoubleAnimation' (HashCode=562002);
target元素是'DoubleAnimation'(HashCode = 562002); target property is 'To' (type 'Nullable`1')
target属性为'To'(类型'Nullable`1')
My Control looks like this: 我的控件看起来像这样:
<Style TargetType="{x:Type local:MyControl}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type local:MyControl}">
<Grid x:Name="RootGrid" >
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="CheckStates">
<VisualState x:Name="Checked">
<Storyboard>
<DoubleAnimation Storyboard.TargetName="someElement"
Storyboard.TargetProperty="Height"
From="0"
To="{Binding RelativeSource={RelativeSource AncestorType=local:MyControl}, Path=CustomControlProperty}"
Duration="0:0:.7" />
...
I tried all ways of Bindings, but it seems that the Animations always takes itself as Scope. 我试过Bindings的所有方法,但似乎Animations总是将自己视为Scope。
Thanks for your help again. 再次感谢您的帮助。
I was able to do this with a BindingProxy
. 我能用
BindingProxy
做到这BindingProxy
。 I find binding proxies to be nonintuitive. 我发现绑定代理是非直观的。 Sometimes they work on the first shot;
有时他们会在第一次拍摄时工作; this one took a little trial and error.
这个尝试了一点试验和错误。 Also, they're a little bit of a hail-mary workaround.
此外,他们是一个有点冰雹的解决方法。
XAML: XAML:
<Grid
x:Name="RootGrid"
>
<Grid.Resources>
<!--
When defined in ControlTemplate.Resources, this failed.
TemplateBinding failed too.
-->
<local:BindingProxy
x:Key="CustomControlPropertyProxy"
Data="{Binding CustomControlProperty, RelativeSource={RelativeSource TemplatedParent}}"
/>
</Grid.Resources>
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="CheckStates">
<VisualState x:Name="Checked">
<Storyboard>
<DoubleAnimation
Storyboard.TargetName="someElement"
Storyboard.TargetProperty="Height"
From="0"
To="{Binding Data, Source={StaticResource CustomControlPropertyProxy}}"
Duration="0:0:5"
/>
</Storyboard>
C# (stolen, not for the first time, from this answer ): C#(被盗,不是第一次, 从这个答案 ):
public class BindingProxy : Freezable
{
#region Overrides of Freezable
protected override Freezable CreateInstanceCore()
{
return new BindingProxy();
}
#endregion
public object Data
{
get { return (object)GetValue(DataProperty); }
set { SetValue(DataProperty, value); }
}
public static readonly DependencyProperty DataProperty =
DependencyProperty.Register("Data", typeof(object),
typeof(BindingProxy));
}
Here's another variant of the XAML, in case you end up binding animation properties to more than one property of the templated parent: 这是XAML的另一个变体,以防您最终将动画属性绑定到模板化父级的多个属性:
<Grid
x:Name="RootGrid"
>
<Grid.Resources>
<local:BindingProxy
x:Key="TemplatedParentProxy"
Data="{Binding ., RelativeSource={RelativeSource TemplatedParent}}"
/>
</Grid.Resources>
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="CheckStates">
<VisualState x:Name="Checked">
<Storyboard>
<DoubleAnimation
Storyboard.TargetName="someElement"
Storyboard.TargetProperty="Height"
From="0"
To="{Binding Data.CustomControlProperty, Source={StaticResource TemplatedParentProxy}}"
Duration="0:0:5"
/>
</Storyboard>
After ruling out TemplateBinding
and {RelativeSource TemplatedParent}
, my next guess was to bind RootGrid.Tag
to CustomControlProperty
and use To="{Binding Tag, ElementName=RootGrid}"
. 在排除
TemplateBinding
和{RelativeSource TemplatedParent}
,我的下一个猜测是将RootGrid.Tag
绑定到CustomControlProperty
并使用To="{Binding Tag, ElementName=RootGrid}"
。 That did not work. 那没用。 While intellisense knew about
RootGrid
in the XAML designer, the Binding
couldn't find RootGrid
at runtime: 虽然intellisense知道XAML设计
RootGrid
中的RootGrid
,但Binding
在运行时找不到RootGrid
:
<DoubleAnimation
Storyboard.TargetName="someElement"
Storyboard.TargetProperty="Height"
From="0"
To="{Binding Tag, ElementName=RootGrid, PresentationTraceSources.TraceLevel=High}"
Duration="0:0:1"
/>
Debug trace: 调试跟踪:
System.Windows.Data Warning: 67 : BindingExpression (hash=15221148): Resolving source
System.Windows.Data Warning: 69 : BindingExpression (hash=15221148): Framework mentor not found
System.Windows.Data Warning: 67 : BindingExpression (hash=15221148): Resolving source (last chance)
System.Windows.Data Warning: 69 : BindingExpression (hash=15221148): Framework mentor not found
System.Windows.Data Error: 2 : Cannot find governing FrameworkElement or FrameworkContentElement for target element. BindingExpression:Path=Tag; DataItem=null; target element is 'DoubleAnimation' (HashCode=44950942); target property is 'To' (type 'Nullable`1')
That "governing FrameworkElement or FrameworkContentElement" jazz is the essential problem with all of the other approaches as well. “管理FrameworkElement或FrameworkContentElement”爵士乐也是所有其他方法的基本问题。 That's where binding proxies come in: Resource lookup isn't limited by that visual tree parent chain stuff.
这就是绑定代理进入的地方:资源查找不受可视树父链的限制。
Edit I realized my answer doesn't work after all. 编辑我意识到我的答案毕竟不起作用。
See this related discussion https://social.msdn.microsoft.com/Forums/vstudio/en-US/027c364f-5d75-424f-aafd-7fb76b10b676/templatebinding-on-storyboard?forum=wpf 请参阅此相关讨论https://social.msdn.microsoft.com/Forums/vstudio/en-US/027c364f-5d75-424f-aafd-7fb76b10b676/templatebinding-on-storyboard?forum=wpf
[...] The
To
property andFrom
property ofColorAnimation
can't be bind with, because of those properties need to be frozen (unchangeable) for the animation to work.[...]
ColorAnimation
的To
属性和From
属性无法绑定,因为这些属性需要被冻结(不可更改)才能使动画ColorAnimation
。So please use specific color to instead of binding.
所以请使用特定的颜色而不是绑定。
This suggests that some animation elements are not supposed to change via dynamic properties. 这表明一些动画元素不应该通过动态属性来改变。 I actually don't know whether this applies to all animations or just to a specific subset.
我实际上不知道这是适用于所有动画还是仅适用于特定子集。
So considering @EdPlunkett answer, it might be worth to investigate, whether subsequent property changes are actually reflected in the animation without errors. 因此,考虑到@EdPlunkett的答案,可能值得研究一下,后续的属性更改是否实际上反映在动画中而没有错误。
You should use {TemplateBinding CustomControlProperty}
for one way binding or {Binding RelativeSource={RelativeSource TemplatedParent},Path=CustomControlProperty}
if you need more binding complexity, instead of trying to find the templated control by other means. 如果需要更多绑定复杂性,则应使用
{TemplateBinding CustomControlProperty}
进行单向绑定或{Binding RelativeSource={RelativeSource TemplatedParent},Path=CustomControlProperty}
,而不是尝试通过其他方式查找模板化控件。
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