Procedura: controllare in modo interattivo un oggetto Clock

Aggiornamento: novembre 2007

La proprietà ClockController di un oggetto Clock consente di avviare, sospendere, riprendere, cercare e arrestare l'oggetto clock, nonché di spostarlo alla fine del segmento di tempo. Solo l'oggetto clock radice di una struttura ad albero delle temporizzazioni può essere controllato in modo interattivo.

Nell'esempio seguente vengono utilizzati vari pulsanti per controllare in modo interattivo clock dell'animazione.

Esempio

/*
  This example shows how to interactively control 
  a root clock.
*/
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Shapes;
using System.Windows.Media.Animation;

namespace Microsoft.Samples.Animation.TimingBehaviors
{
    public class ClockControllerExample : Page
    {

        private AnimationClock myControllableClock;
        private Button seekButton;
        private TextBox seekAmountTextBox;
        private ListBox timeSeekOriginListBox;

        public ClockControllerExample()
        {
            StackPanel mainPanel = new StackPanel();

            // Create a rectangle to animate.
            Rectangle animatedRectangle = new Rectangle();
            animatedRectangle.Width = 100;
            animatedRectangle.Height = 100;
            animatedRectangle.Fill = Brushes.Orange;
            mainPanel.Children.Add(animatedRectangle);

            // Create a DoubleAnimation to
            // animate its width.
            DoubleAnimation widthAnimation = 
                new DoubleAnimation(
                    100,
                    500, 
                    new Duration(TimeSpan.FromSeconds(5)));

            // Create a clock from the animation.
            myControllableClock = widthAnimation.CreateClock();

            // Apply the clock to the rectangle's Width property.
            animatedRectangle.ApplyAnimationClock(
                Rectangle.WidthProperty, myControllableClock);
            myControllableClock.Controller.Stop();

            //
            // Create some buttons to control the clock.
            //

            // Create a button to begin the clock.
            Button beginButton = new Button();
            beginButton.Content = "Begin";
            beginButton.Click += 
                new RoutedEventHandler(beginButton_Clicked);
            mainPanel.Children.Add(beginButton);

            // Create a button to pause the clock. 
            Button pauseButton = new Button();
            pauseButton.Content = "Pause";
            pauseButton.Click += 
                new RoutedEventHandler(pauseButton_Clicked);
            mainPanel.Children.Add(pauseButton);    

            // Create a button to resume the clock. 
            Button resumeButton = new Button();
            resumeButton.Content = "Resume";
            resumeButton.Click += 
                new RoutedEventHandler(resumeButton_Clicked);
            mainPanel.Children.Add(resumeButton); 

            // Create a button to advance the clock to
            // its fill period. 
            Button skipToFillButton = new Button();
            skipToFillButton.Content = "Skip to Fill";
            skipToFillButton.Click += 
                new RoutedEventHandler(skipToFillButton_Clicked);
            mainPanel.Children.Add(skipToFillButton);       

            // Create a button to stop the clock.
            Button stopButton = new Button();
            stopButton.Content = "Stop";
            stopButton.Click += 
                new RoutedEventHandler(stopButton_Clicked);
            mainPanel.Children.Add(stopButton);  

            //
            // Create some controls the enable the user to
            // seek the clock. 
            //

            StackPanel seekDetailsPanel = new StackPanel();
            seekDetailsPanel.Margin = new Thickness(0,20,0,20);
            seekDetailsPanel.Orientation = Orientation.Horizontal;
            Label seekAmountLabel = new Label();
            seekAmountLabel.Content = "Seek amount:";
            seekDetailsPanel.Children.Add(seekAmountLabel);

            // Create a text box so that the user can
            // specify the amount by which to seek.
            seekAmountTextBox = new TextBox();
            seekAmountTextBox.Text = "0:0:1";
            seekAmountTextBox.VerticalAlignment = VerticalAlignment.Top;
            seekAmountTextBox.TextChanged += 
                new TextChangedEventHandler(seekAmountTextBox_TextChanged);
            seekDetailsPanel.Children.Add(seekAmountTextBox);

            Label timeSeekOriginLabel = new Label();
            timeSeekOriginLabel.Content = "Seek Origin:";
            seekDetailsPanel.Children.Add(timeSeekOriginLabel);

            // Create a ListBox so the user can
            // select whether the seek time is relative
            // to the clock's BeginTime or Duration.
            timeSeekOriginListBox = new ListBox();
            timeSeekOriginListBox.Items.Add("BeginTime");
            timeSeekOriginListBox.Items.Add("Duration");
            timeSeekOriginListBox.Padding = new Thickness(5);
            timeSeekOriginListBox.SelectedIndex = 0;
            seekDetailsPanel.Children.Add(timeSeekOriginListBox);  

            // Create a button to seek the clock.
            seekButton = new Button();
            seekButton.Content = "Seek";
            seekButton.Click += new RoutedEventHandler(seekButton_Clicked);  
            seekDetailsPanel.Children.Add(seekButton);
            mainPanel.Children.Add(seekDetailsPanel);        

            this.Content = mainPanel;
        }

        // Starts the clock.
        private void beginButton_Clicked(object sender, RoutedEventArgs e)
        {
            myControllableClock.Controller.Begin();            
        }

        // Pauses the clock.
        private void pauseButton_Clicked(object sender, RoutedEventArgs e)
        {
            myControllableClock.Controller.Pause();           
        }

        // Resumes the clock.
        private void resumeButton_Clicked(object sender, RoutedEventArgs e)
        {
            myControllableClock.Controller.Resume();           
        }    

        // Adances the clock to its fill period.
        private void skipToFillButton_Clicked(object sender, RoutedEventArgs e)
        {
            myControllableClock.Controller.SkipToFill();           
        }     

        // Stops the clock.
        private void stopButton_Clicked(object sender, RoutedEventArgs e)
        {
            myControllableClock.Controller.Stop();           
        }    

        // Seeks the clock.
        private void seekButton_Clicked(object sender, RoutedEventArgs e)
        {


            try {

                // Obtain the seek amount from the seekAmountTextBox TextBox.
                TimeSpan seekAmount = TimeSpan.Parse(seekAmountTextBox.Text);

                // Determine the seek origin by reading the selected value
                // from the timeSeekOriginListBox ListBox.
                TimeSeekOrigin selectedOrigin = 
                    (TimeSeekOrigin)Enum.Parse(typeof(TimeSeekOrigin), 
                    (string)timeSeekOriginListBox.SelectedItem);

                // Seek to the specified location.
                myControllableClock.Controller.Seek(seekAmount, selectedOrigin); 

            }catch(FormatException formatEx)
            {
                MessageBox.Show(seekAmountTextBox.Text 
                    + " is not a valid TimeSpan. Please enter another value.");

                // Disable the seek button until the user enters another value.
                seekButton.IsEnabled = false;
            }
        }

        // Verifies that seekAmountTextBox has text content.
        // If there is no text, disable the seek button.
        private void seekAmountTextBox_TextChanged(object sender, TextChangedEventArgs e)
        {
            TextBox theTextBox = (TextBox)e.Source;
            if (theTextBox.Text == null || theTextBox.Text.Length < 1)
                seekButton.IsEnabled = false;
            else 
                seekButton.IsEnabled = true;


        }

    }
}

Vedere anche

Attività

Procedura: animare una proprietà utilizzando uno storyboard

Concetti

Cenni preliminari sull'animazione