Checked VisualState is not triggered after RadioButton is re-enabled

问题

I'm working with a custom RadioButton control that is allows the user to give a rating between 1 and 5 depending on the selected RadioButton.

However, there are times in my application that the 5 RadioButtons are disabled, and then re-enabled. When this happens the VisualState for the Checked RadioButton doesn't activate. Instead, all 5 RadioButtons appear as the Normal state.

Why is this happening? How can I resolve this?

Here is the example of the RadioButtons that I'm using.

If I start by selecting the first group of 5 RadioButtons, and make a selection, then everything may appear as the above image does.

But, if I select the second group of 5 RadioButtons, my control is designed so that the first group will disable. This works fine, and the second group enables properly. After that, if I select the first group again, every Radiobutton will appear with the Normal VisualState. This is a problem, because my program knows that behind the scenes that #1 is still Checked. The Checked VisualState is NOT triggered, so it looks something like this:

The goal here is that the Checked VisualState will be resumed as it appears in the first image.

Here is the corresponding XAML code for the VisualStates:

<VisualStateManager.VisualStateGroups>
    <VisualStateGroup x:Name="CommonStates">
        <VisualState Name="Normal"/>
        <VisualState Name="Disabled">
            <Storyboard>
                <ColorAnimation Storyboard.TargetName="FillBrush" Storyboard.TargetProperty="Color" To="#FFEEEEEE" Duration="0"/>
                <ColorAnimation Storyboard.TargetName="StrokeBrush" Storyboard.TargetProperty="Color" To="#FF777777" Duration="0"/>
                <DoubleAnimation Storyboard.TargetName="MoodEllipse" Storyboard.TargetProperty="StrokeThickness" To="1" Duration="0"/>
                <ColorAnimation Storyboard.TargetName="Presenter" Storyboard.TargetProperty="(TextBlock.Foreground).Color" To="#FF777777" Duration="0"/>
            </Storyboard>
        </VisualState>
    </VisualStateGroup>
    <VisualStateGroup x:Name="CheckStates">
        <VisualState Name="Checked">
            <Storyboard>
                <ParallelTimeline>
                    <ColorAnimation Storyboard.TargetName="FillBrush" Storyboard.TargetProperty="Color" To="#FFC5F5FF" Duration="0:0:0.05"/>
                    <ColorAnimation Storyboard.TargetName="StrokeBrush" Storyboard.TargetProperty="Color" To="#FF12394F" Duration="0:0:0.05"/>
                    <DoubleAnimation Storyboard.TargetName="MoodEllipse" Storyboard.TargetProperty="StrokeThickness" To="2" Duration="0:0:0.05"/>
                </ParallelTimeline>
            </Storyboard>
        </VisualState>
        <VisualState Name="Unchecked"/>
        <VisualState Name="Indeterminate"/>
    </VisualStateGroup>
</VisualStateManager.VisualStateGroups>

This XAML code seems to be in accordance to how to use VisualStates, but I suppose there must be something wrong with it.

I've referenced these pages:

Customizing the Appearance of an Existing Control by Creating a ControlTemplate
RadioButton Styles and Templates

As some additional notes, I've noticed that the Checked VisualState can be triggered if I click one of the Unchecked RadioButtons. At this point, everything is works properly --until the group of RadioButtons is disabled & re-enabled.

Also, I've experience even stranger behavior for the Checked VisualState when I didn't include the empty Unchecked VisualState in the above XAML code.

Any insight about why the VisualStates are behaving strangely would be greatly appreciated. Thanks much!

EDIT:

I'm not sure if it matters, but the group of RadioButtons are disabled because they are in StackPanels whose IsEnabled property is bound to the outside RadioButton's IsChecked property:

<StackPanel IsEnabled="{Binding RelativeSource={RelativeSource AncestorType={x:Type RadioButton}}, Path=IsChecked}">

回答1:

Apparently, the problem is that I am using the same target properties within two different VisualStateGroups, yet I'm not sure why this causes the problem.

In order to have the desired affect, which is to display the Checked behavior after re-enabling, I created another Ellipse which is overlaid of the the original Ellipse.

The original Ellipse is fully opaque and it's Fill/Stroke properties are modified by the CheckStates group ONLY.

The new Ellipse is initially fully transparent (Opacity="0"), but the Disabled state causes the opacity to change to fully opaque.

This new Ellipse fades into into view and covers up the original Ellipse, which is showing the appearance of the Checked/Unchecked states. This causes the overall result of the RadioButton to appear Disabled.

This fixed the problem describe in the OP, but it introduces a new issue: the transition from the Disabled state to the Checked state is immediate. This can be resolve by including this VisualTransition in the CommonStates group:

<VisualTransition From="Disabled" To="Checked" GeneratedDuration="0:0:0.25"/>

Here is the final XAML used to solve the problem:

<VisualStateManager.VisualStateGroups>
    <VisualStateGroup x:Name="CommonStates">
        <VisualStateGroup.Transitions>
            <VisualTransition From="Disabled" To="Checked" GeneratedDuration="0:0:0.25"/>
        </VisualStateGroup.Transitions>
        <VisualState Name="Normal"/>
        <VisualState Name="Disabled">
            <Storyboard>
                <DoubleAnimation Storyboard.TargetName="EllipseOverlay" Storyboard.TargetProperty="Opacity" To="1" Duration="0:0:0.15"/>
            </Storyboard>
        </VisualState>
    </VisualStateGroup>
    <VisualStateGroup x:Name="CheckStates">
        <VisualState Name="Checked">
            <Storyboard>
                <ParallelTimeline>
                    <ColorAnimation Storyboard.TargetName="FillBrush" Storyboard.TargetProperty="Color" To="#FFC5F5FF" Duration="0:0:0.05"/>
                    <ColorAnimation Storyboard.TargetName="StrokeBrush" Storyboard.TargetProperty="Color" To="#FF12394F" Duration="0:0:0.05"/>
                    <DoubleAnimation Storyboard.TargetName="MoodEllipse" Storyboard.TargetProperty="StrokeThickness" To="2" Duration="0:0:0.05"/>
                </ParallelTimeline>
            </Storyboard>
        </VisualState>
        <VisualState Name="Unchecked"/>
        <VisualState Name="Indeterminate"/>
    </VisualStateGroup>
</VisualStateManager.VisualStateGroups>

In my control, I have this Ellipse appear after my original Ellipse, causing the new one to appear on top when the opacity increases. Below is the new Ellipse:

<Ellipse x:Name="EllipseOverlay" StrokeThickness="1" Opacity="0" Fill="#FFEEEEEE" Stroke="#FF777777"/>

Note that this Ellipse contains the Fill/Stroke properties that were using the the OP's Disabled VisualState.

来源：https://stackoverflow.com/questions/25801126/checked-visualstate-is-not-triggered-after-radiobutton-is-re-enabled

标签

wpf

xaml

radio-button

visualstates