Reverse Triggered Animation If Method Fails Using Xaml, Not Code Behind

Question

I have a login form with a button (btnLogin). When a user clicks btnLogin, the following Storyboard is triggered to disable btnLogin, txtUsername, pbPassword ...

<EventTrigger RoutedEvent="Button.Click">
    <EventTrigger.Actions>
        <BeginStoryboard>
            <Storyboard>
                <BooleanAnimationUsingKeyFrames Storyboard.TargetProperty="IsEnabled" FillBehavior="HoldEnd">
                    <DiscreteBooleanKeyFrame KeyTime="00:00:00" Value="False" />
                </BooleanAnimationUsingKeyFrames>
                <BooleanAnimationUsingKeyFrames Storyboard.TargetName="txtUsername" Storyboard.TargetProperty="IsEnabled" FillBehavior="HoldEnd">
                    <DiscreteBooleanKeyFrame KeyTime="00:00:00" Value="False" />
                </BooleanAnimationUsingKeyFrames>
                <BooleanAnimationUsingKeyFrames Storyboard.TargetName="pbPassword" Storyboard.TargetProperty="IsEnabled" FillBehavior="HoldEnd">
                    <DiscreteBooleanKeyFrame KeyTime="00:00:00" Value="False" />
                </BooleanAnimationUsingKeyFrames>
            </Storyboard>
        </BeginStoryboard>
    </EventTrigger.Actions>
</EventTrigger>

... as this Storyboard runs, the Button.Click event is also attached to a btnLogin_Click method which verifies the users credentials. Fair enough!

Currently, if the login attempt fails, I have to use the following (dirty?!) code in btnLogin_Click to re-enable the btnLogin, txtUsername, pbPassword controls so the details can be re-entered ...

btnLogin.Triggers.Clear();
btnLogin.BeginAnimation(UIElement.IsEnabledProperty, null);
txtUsername.BeginAnimation(UIElement.IsEnabledProperty, null);
pbPassword.BeginAnimation(UIElement.IsEnabledProperty, null);

Can i handle this re-enabling using Xaml instead? I'm sure I can, I just can't figure out how to do it?!

Thanks for your help :O)

---

UPDATE

I've tried using EnterActions and ExitActions as suggested by bars222, but this approach has no means to determine if the btnLogin_Click event resulted in a successful or unsuccessful login.

Answer 1

If I clearly understand, you want to set IsEnabled to true after the login attempt. In that case you can use EventTrigger.EnterActions and EventTrigger.ExitActions triggers. Here some example.

<EventTrigger RoutedEvent="Button.Click">
    <EventTrigger.EnterActions>
        <BeginStoryboard>
            <Storyboard>
                <BooleanAnimationUsingKeyFrames Storyboard.TargetProperty="IsEnabled" FillBehavior="HoldEnd">
                    <DiscreteBooleanKeyFrame KeyTime="00:00:00" Value="False" />
                </BooleanAnimationUsingKeyFrames>
            </Storyboard>
        </BeginStoryboard>
    </EventTrigger.EnterActions>
    <EventTrigger.ExitActions>
        <BeginStoryboard>
            <Storyboard>
                <BooleanAnimationUsingKeyFrames Storyboard.TargetProperty="IsEnabled" FillBehavior="HoldEnd">
                    <DiscreteBooleanKeyFrame KeyTime="00:00:00" Value="True" />
                </BooleanAnimationUsingKeyFrames>
            </Storyboard>
        </BeginStoryboard>
    </EventTrigger.ExitActions>
</EventTrigger>

Update

Solution with data binding. You can create some property, that indicates authorization process. You should update this during auth process.

private bool _isAuth;
public bool IsAuth
{
    get { return _isAuth; }
    set { _isAuth = value; NotifyPropertyChanged( "IsAuth" ); }
}

#region INotifyPropertyChanged Members
public event PropertyChangedEventHandler PropertyChanged;
#endregion
protected void NotifyPropertyChanged( String info )
{
    if ( PropertyChanged != null )
    {
        PropertyChanged( this, new PropertyChangedEventArgs( info ) );
    }
}

You should set DataContext of these elements. For example, if you created property in authorization window. You can write in constructor.

this.DataContext = this;

And bind it to your elements to enable/disable it.

<Button Click="Button_Click" IsEnabled="{Binding IsAuth}" />