Question

Possible Duplicate:
Start Storyboard When Text Changes

I’ve created a animation:

<phone:PhoneApplicationPage
    ...>

    <phone:PhoneApplicationPage.Resources>
        <Storyboard x:Name="MessageFadeInOut" Storyboard.TargetProperty="Opacity">
            <DoubleAnimation From="0" To="1" Duration="0:0:1" BeginTime="0:0:0" />
            <DoubleAnimation From="1" To="1" Duration="0:0:1" BeginTime="0:0:1" />
            <DoubleAnimation From="1" To="0" Duration="0:0:1" BeginTime="0:0:2" />
        </Storyboard>
    </phone:PhoneApplicationPage.Resources>

What I’m trying to do where is have something fade in, stay for a bit then fade out.

I trigger it by:

private void Unit_Tap_1(object sender, System.Windows.Input.GestureEventArgs e)
        {
            Storyboard sb = this.Resources["MessageFadeInOut"] as Storyboard;
            Storyboard.SetTarget(sb, this.Message);
            sb.Begin();
        } 

But on the sb.Begin() I get “System.InvalidOperationException”. How come? Message is a Image

Answer 1

I’m not sure what “Message” is in this context, and that might be the reason why you’re seeing this exception. Or it might not be .

Either way, you shouldn’t grab Storyboards and start those manually. You should use VisualStateManager to manage your visual states by encapsulating a storyboard in each state. You can read more about this @ Start Storyboard When Text Changes

A good way to get started in VSM would be to watch these videos by Steve White in the Expression Blend 2 launch:

• Adding Control States @ http://msdn.microsoft.com/en-us/expression/ff898424
• Create Custom Buttons @ http://msdn.microsoft.com/en-us/expression/ff921363
• Customize a Checkbox’s Checkmark @ http://msdn.microsoft.com/en-us/expression/ff921365
• Use an In-State Animation @ http://msdn.microsoft.com/en-us/expression/ff921380

Each of these videos is part of a series, so consider watching the rest of the series. There are also articles you can read @ http://www.interact-sw.co.uk/iangblog/2008/06/10/visual-state