GoToState在UserControl中不适用于ControlTemplate [英] GoToState does not work for ControlTemplate in UserControl

问题描述

我完全迷失了，我非常感谢您对此的帮助。

I am totally lost and I would really appreciate your help on this.

我的最终目标是创建一个包含两个控制模板的用户控件。广场和一个圆。基于类型，控件将显示一个或另一个。当鼠标进入形状时，不透明度将变为0.2。

My final goal is to create a user control that will contain two control templates. Square and a Circle. Based on a type the control will display one or the other. When the mouse enters the shape the Opacity will change to 0.2.

第一部分工作，但不透明度不变。事件被触发，并调用GoToState，但没有结果。不透明度为1。

The first part works but the Opacity does not change. The event is triggered and a GoToState is called, but with no result. The Opacity stays 1.

我的XAML：

<UserControl.Resources>

    <ControlTemplate x:Key="TemplateSquare" TargetType="{x:Type local:KeyControl}">

        <Canvas x:Name="MainCanvas" VerticalAlignment="Center" HorizontalAlignment="Center">

            <VisualStateManager.VisualStateGroups>
                <VisualStateGroup x:Name="CommonStates">
                    <VisualState x:Name="Normal" />
                    <VisualState x:Name="MouseOver">
                        <Storyboard>
                            <DoubleAnimation Storyboard.TargetName="CenterRectangle" Storyboard.TargetProperty="(UIElement.Opacity)" Duration="0" To=".2"/>
                        </Storyboard>
                    </VisualState>
                </VisualStateGroup>
            </VisualStateManager.VisualStateGroups>

            <Rectangle x:Name="CenterRectangle" Fill="Red" Width="100" Height="100"></Rectangle>

        </Canvas>

    </ControlTemplate>    
</UserControl.Resources> 
<!-- IF I MOVE THE CANVAS HERE THE OPACITY CHANGES ON MOUSE OVER -->

Codebehind：

Codebehind:

public partial class KeyControl : UserControl
{
    private bool _isPressed = false;
    private bool _isMouseOver = false;

    public KeyControl()
    {
        InitializeComponent();

        this.Loaded += new RoutedEventHandler(KeyControl_Loaded);
    }


    private void KeyControl_Loaded(object sender, RoutedEventArgs e)
    {
        //this will be set in the Type setter
        this.Template = this.FindResource("TemplateSquare") as ControlTemplate;

        this.MouseEnter += new MouseEventHandler(CorePart_MouseEnter);
        this.MouseLeave += new MouseEventHandler(CorePart_MouseLeave);

        GoToState(false);
    }

    private void GoToState(bool useTransitions)
    {
        if (_isPressed)
            VisualStateManager.GoToState(this, "Pressed", useTransitions);
        else if (_isMouseOver)
            VisualStateManager.GoToState(this, "MouseOver", useTransitions);
        else
            VisualStateManager.GoToState(this, "Normal", useTransitions);
    }

    private void CorePart_MouseLeave(object sender, MouseEventArgs e)
    {
        _isMouseOver = false;
        GoToState(true);
    }

    private void CorePart_MouseEnter(object sender, MouseEventArgs e)
    {
        _isMouseOver = true;
        GoToState(true);
    }
}

有人可以告诉我哪里可能有问题吗？

Can somebody please tell me where the problem could be?

谢谢

推荐答案

UserControl使其内容为root 元素，用于定位VisualStateGroups。如果你使用Reflector并查看UserControl.StateGroupsRoot，你会看到它看起来像：

The UserControl makes it's Content the "root" element, which is used to locate the VisualStateGroups. If you use Reflector and look at UserControl.StateGroupsRoot, you'd see it looks like:

internal override FrameworkElement StateGroupsRoot {
    get {
        return (base.Content as FrameworkElement);
    }
}

$ b <

While FrameworkElement (and thus most other elements) use:

internal virtual FrameworkElement StateGroupsRoot {
    get {
        return (this._templateChild as FrameworkElement);
    }
}

设置Template属性时，Content属性仍然为null。将画布移动到资源下面时，您正在设置内容属性。因此，在这种情况下可以找到视觉状态组。

When setting the Template property, the Content property will still be null. When you move the Canvas to be below Resources, you are setting the Content property. So the visual state groups can be found in that case.

您可以通过直接更改从ContentControl导出的控件，绕过UserControl来解决此问题。只需将UserControl引用更改为XAML中的ContentControl和代码隐藏。

You can work around this by changing your control derive from ContentControl directly, and bypass UserControl. Simply change UserControl references to ContentControl in your XAML and code-behind.

这篇关于GoToState在UserControl中不适用于ControlTemplate的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！