wpf use VisualStateManager to change Visibility

Question

I'm working on transitioning some code from silverlight to WPF, and my VisualStates are not working correctly.

I am using visualstatemanager to control the visibility of some text fields. I am not using any transitions to animate the change, I just want the fields to be collapsed in one state, then visible in another.

Xaml from silverlight:

<VisualStateManager.VisualStateGroups>
        <VisualStateGroup x:Name="LostPasswordStates">
            <VisualState x:Name="LostPassword_Start">
                <Storyboard>

                    <ObjectAnimationUsingKeyFrames Storyboard.TargetName="lbl_UserName" Storyboard.TargetProperty="(UIElement.Visibility)">
                        <DiscreteObjectKeyFrame KeyTime="00:00:00" Value="Visible" />
                    </ObjectAnimationUsingKeyFrames>

                    <ObjectAnimationUsingKeyFrames Storyboard.TargetName="txt_UserName" Storyboard.TargetProperty="(UIElement.Visibility)">
                        <DiscreteObjectKeyFrame KeyTime="00:00:00" Value="Visible" />
                    </ObjectAnimationUsingKeyFrames>

                    <ObjectAnimationUsingKeyFrames Storyboard.TargetName="txt_UserName" Storyboard.TargetProperty="(TextBox.IsReadOnly)">
                        <DiscreteObjectKeyFrame KeyTime="00:00:00" Value="False" />
                    </ObjectAnimationUsingKeyFrames>

                </Storyboard>
            </VisualState>
            <VisualState x:Name="LostPassword_Success">
                <Storyboard>

                    <ObjectAnimationUsingKeyFrames Storyboard.TargetName="lbl_UserName" Storyboard.TargetProperty="(UIElement.Visibility)">
                        <DiscreteObjectKeyFrame KeyTime="00:00:00" Value="Collapsed" />
                    </ObjectAnimationUsingKeyFrames>

                    <ObjectAnimationUsingKeyFrames Storyboard.TargetName="txt_UserName" Storyboard.TargetProperty="(UIElement.Visibility)">
                        <DiscreteObjectKeyFrame KeyTime="00:00:00" Value="Collapsed" />
                    </ObjectAnimationUsingKeyFrames>

                    <ObjectAnimationUsingKeyFrames Storyboard.TargetName="btn_Reset" Storyboard.TargetProperty="(UIElement.Visibility)">
                        <DiscreteObjectKeyFrame KeyTime="00:00:00" Value="Collapsed" />
                    </ObjectAnimationUsingKeyFrames>

                </Storyboard>
            </VisualState>
        </VisualStateGroup>
    </VisualStateManager.VisualStateGroups>

I get the following exception :

An unhandled exception of type 'System.Windows.Media.Animation.AnimationException' occurred in PresentationCore.dll

Additional information: Cannot animate the 'Visibility' property on a 'System.Windows.Controls.TextBox' using a 'System.Windows.Media.Animation.ObjectAnimationUsingKeyFrames'. For details see the inner exception.

So my question to you is:

If I can't use a System.Windows.Media.Animation.ObjectAnimationUsingKeyFrames for this, what should I be using?

Which version of WPF? I've got a virtually identical storyboard animating the UIElement.Visibility property on a Border which works fine in 4.0 and 4.5. — Richard Deeming
The only difference I can see is that I'm using {x:Static Visibility.Visible} as the Value, instead of just Visible. — Richard Deeming
you're right, I did change the the values to the {x:Static Visibility.Collapsed} format in my wpf code. (I copied the text above stright from the silverlight version) Also, I'm using .net 4.5 — Shaboboo
UIElement.Visibility seems to work on some elements and not others. Label for example doesn't seem to have an issue, but Textbox and buttons do have the issue. — Shaboboo

Richard Deeming Richard Deeming · Accepted Answer · 2015-05-28T15:58:48

This works for me, using .NET 4.5:

<VisualStateManager.VisualStateGroups>
    <VisualStateGroup x:Name="LostPasswordStates">
        <VisualState x:Name="LostPassword_Start">
            <Storyboard>

                <ObjectAnimationUsingKeyFrames Storyboard.TargetName="lbl_UserName" Storyboard.TargetProperty="(UIElement.Visibility)">
                    <DiscreteObjectKeyFrame KeyTime="00:00:00" Value="{x:Static Visibility.Visible}" />
                </ObjectAnimationUsingKeyFrames>

                <ObjectAnimationUsingKeyFrames Storyboard.TargetName="txt_UserName" Storyboard.TargetProperty="(UIElement.Visibility)">
                    <DiscreteObjectKeyFrame KeyTime="00:00:00" Value="{x:Static Visibility.Visible}" />
                </ObjectAnimationUsingKeyFrames>

                <BooleanAnimationUsingKeyFrames Storyboard.TargetName="txt_UserName" Storyboard.TargetProperty="(TextBox.IsReadOnly)">
                    <DiscreteBooleanKeyFrame KeyTime="00:00:00" Value="False" />
                </BooleanAnimationUsingKeyFrames>

            </Storyboard>
        </VisualState>
        <VisualState x:Name="LostPassword_Success">
            <Storyboard>

                <ObjectAnimationUsingKeyFrames Storyboard.TargetName="lbl_UserName" Storyboard.TargetProperty="(UIElement.Visibility)">
                    <DiscreteObjectKeyFrame KeyTime="00:00:00" Value="{x:Static Visibility.Collapsed}" />
                </ObjectAnimationUsingKeyFrames>

                <ObjectAnimationUsingKeyFrames Storyboard.TargetName="txt_UserName" Storyboard.TargetProperty="(UIElement.Visibility)">
                    <DiscreteObjectKeyFrame KeyTime="00:00:00" Value="{x:Static Visibility.Collapsed}" />
                </ObjectAnimationUsingKeyFrames>

                <ObjectAnimationUsingKeyFrames Storyboard.TargetName="btn_Reset" Storyboard.TargetProperty="(UIElement.Visibility)">
                    <DiscreteObjectKeyFrame KeyTime="00:00:00" Value="{x:Static Visibility.Collapsed}" />
                </ObjectAnimationUsingKeyFrames>

            </Storyboard>
        </VisualState>
    </VisualStateGroup>
</VisualStateManager.VisualStateGroups>

There are two changes to your current code:

Instead of "Collapsed" and "Visible", the Value is set to "{x:Static Visibility.Collapsed}" and "{x:Static Visibility.Visible}";
The IsReadOnly property uses a BooleanAnimationUsingKeyFrames instead of an ObjectAnimationUsingKeyFrames;

wpf use VisualStateManager to change Visibility

2 Answers