Microsoft Surface 示例--Social Stream for Microsoft Surface 2.0

      Social Stream for Microsoft Surface 是微软与Stimulant, Inc协作创建的一个简单的应用程序示例，此示例程序可以把社区的照片、tweets通过这个应用程序流畅的触摸和翻动分享给大家，值得我们一览。

示例中的代码：RiverContentItem.cs

using System; 
using System.ComponentModel; 
using System.Globalization; 
using System.Windows; 
using System.Windows.Controls; 
using System.Windows.Media.Animation; 
using FeedProcessor; 
using FeedProcessor.Enums; 
using FeedProcessor.FeedItems; 
using Microsoft.Surface.Presentation.Controls; 
using SocialStream.Controls.RiverContent; 
using SocialStream.Helpers; 
using SocialStream.Properties; 
 
namespace SocialStream.Controls 
{ 
    /// <summary> 
    /// Represents a content item in the river. Manages the display of content within itself and transitions between large and small content. 
    /// </summary> 
    internal class RiverContentItem : RiverItemBase 
    { 
        #region Private fields 
 
        /// <summary> 
        /// The content to display when the first half of the flash animation completes. 
        /// </summary> 
        private UserControl _nextState; 
 
        /// <summary> 
        /// The current item being rendered. 
        /// </summary> 
        private FeedItem _feedItem; 
 
        /// <summary> 
        /// The renderer for ImageFeedItems when in the river. 
        /// </summary> 
        private SmallImage _smallImage; 
 
        /// <summary> 
        /// The renderer for NewsFeedItems when in the river. 
        /// </summary> 
        private SmallNews _smallNews; 
 
        /// <summary> 
        /// The renderer for StatusFeedItems when in the river. 
        /// </summary> 
        private SmallTweet _smallTweet; 
 
        /// <summary> 
        /// The button to ban a user. 
        /// </summary> 
        private SurfaceButton _banBtn; 
 
        /// <summary> 
        /// The button to delete a specific item. 
        /// </summary> 
        private SurfaceButton _deleteBtn; 
 
        /// <summary> 
        /// An animation shown for especially new items. 
        /// </summary> 
        private Storyboard _breaking; 
 
        /// <summary> 
        /// The ItemProxy that this item is a part of. 
        /// </summary> 
        private ItemProxy _parentProxy; 
 
        #endregion 
 
        /// <summary> 
        /// When overridden in a derived class, is invoked whenever application code or internal processes call <see cref="M:System.Windows.FrameworkElement.ApplyTemplate"/>. 
        /// </summary> 
        public override void OnApplyTemplate() 
        { 
            _smallImage = GetTemplateChild("PART_SmallImage") as SmallImage; 
            _smallNews = GetTemplateChild("PART_SmallNews") as SmallNews; 
            _smallTweet = GetTemplateChild("PART_SmallTweet") as SmallTweet; 
            _banBtn = GetTemplateChild("PART_BanBtn") as SurfaceButton; 
            _deleteBtn = GetTemplateChild("PART_DeleteBtn") as SurfaceButton; 
 
            _banBtn.Click += AdminBtn_Click; 
            _deleteBtn.Click += AdminBtn_Click; 
 
            _breaking = (Template.Resources["Breaking"] as Storyboard).Clone(); 
 
            _parentProxy = this.FindVisualParent<ItemProxy>(); 
 
            if (_parentProxy != null) 
            { 
                _smallImage.Image.ImageLoaded += (sender, e) => _parentProxy.IsEnabled = true; 
            } 
 
            base.OnApplyTemplate(); 
        } 
 
        #region RiverItemBase 
 
        /// <summary> 
        /// Called by the river when the item should retrieve data from its data source. 
        /// </summary> 
        /// <param name="state">A definition which describes the size and position of this item in the river.</param> 
        /// <param name="maintainUnblockedData">if set to <c>true</c> [maintain unblocked data].</param> 
        /// <returns> 
        /// The data that this item will render. If null, the item won't be shown. 
        /// </returns> 
        internal override object GetData(RiverItemState state, bool maintainUnblockedData) 
        { 
            if (DesignerProperties.GetIsInDesignMode(this)) 
            { 
                return new object(); 
            } 
            else if (AppState.Instance.FeedProcessor != null) 
            { 
                if (maintainUnblockedData && _feedItem != null && _feedItem.BlockReason == BlockReason.None) 
                { 
                    return _feedItem; 
                } 
 
                FeedItem feedItem = null; 
 
                if (state.RowSpan == state.ColumnSpan) 
                { 
                    // If it's square, be an image. 
                    feedItem = AppState.Instance.FeedProcessor.GetNextItem(ContentType.Image); 
                } 
                else 
                { 
                    // If not, be twitter or news. 
                    feedItem = AppState.Instance.FeedProcessor.GetNextItem(ContentType.Status | ContentType.News); 
                } 
 
                return feedItem; 
            } 
 
            return null; 
        } 
 
        /// <summary> 
        /// Called by the river when the item should render some data. 
        /// </summary> 
        /// <param name="state">A definition which describes the size and position of this item in the river.</param> 
        /// <param name="data">The data that the river is requesting to be rendered. The item can override this and return different data if needed.</param> 
        /// <returns> 
        /// The data that this item will render. If null, the item won't be shown. 
        /// </returns> 
        internal override object RenderData(RiverItemState state, object data) 
        { 
            UserControl visualState = null; 
            object finalData = data; 
 
            if (DesignerProperties.GetIsInDesignMode(this)) 
            { 
                if (state.RowSpan == state.ColumnSpan) 
                { 
                    visualState = _smallImage; 
                } 
                else if (App.Random.NextDouble() > .5) 
                { 
                    visualState = _smallNews; 
                } 
                else 
                { 
                    visualState = _smallTweet; 
                } 
            } 
            else if (AppState.Instance.IsInitialized) 
            { 
                _feedItem = data as FeedItem; 
 
                if (_feedItem != null && _feedItem.BlockReason != BlockReason.None) 
                { 
                    // This object is being rendered from history, but it got blocked since it was last displayed. Reject this content and get new content. 
                    finalData = _feedItem = GetData(state, false) as FeedItem; 
                } 
 
                if (_feedItem is ImageFeedItem) 
                { 
                    // visualState = removed ? _largeImage as UserControl : _smallImage as UserControl; 
                    visualState = _smallImage as UserControl; 
                } 
                else if (_feedItem is NewsFeedItem) 
                { 
                    // visualState = removed ? _largeNews as UserControl : _smallNews as UserControl; 
                    visualState = _smallNews as UserControl; 
                } 
                else if (_feedItem is StatusFeedItem) 
                { 
                    // visualState = removed ? _largeTweet as UserControl : _smallTweet as UserControl; 
                    visualState = _smallTweet as UserControl; 
                } 
 
                DataContext = _feedItem; 
 
                if (_feedItem is ImageFeedItem && _parentProxy != null) 
                { 
                    // Disable the item while it's loading. 
                    _parentProxy.IsEnabled = _smallImage.Image.BitmapImage != null; 
                } 
 
                _banBtn.Visibility = _feedItem != null && !string.IsNullOrEmpty(_feedItem.Author) ? Visibility.Visible : Visibility.Hidden; 
            } 
 
            GoToState(visualState); 
 
            if (_feedItem != null && DateTime.Now - _feedItem.Date <= Settings.Default.NewItemAlert) 
            { 
                // Show the "breaking" animation for new items. 
                _breaking.Begin(this, Template, true); 
            } 
 
            return finalData; 
        } 
 
        /// <summary> 
        /// Called by the river when this item is being hidden because it scrolled out of view. 
        /// </summary> 
        internal override void Cleanup() 
        { 
            _feedItem = null; 
            _breaking.Stop(this); 
            DataContext = null; 
        } 
 
        /// <summary> 
        /// Called when the item is removed from the river by the user. 
        /// </summary> 
        /// <returns>Sizing restrictions for the item once its in the river.</returns> 
        internal override RiverSize Removed() 
        { 
            RiverSize riverSize = new RiverSize { MaxSize = DesiredSize, RemovedSize = DesiredSize, MinSize = DesiredSize }; 
            return riverSize; 
        } 
 
        /// <summary> 
        /// Called when the item has been removed from the river and its growth animation has completed. 
        /// </summary> 
        internal override void RemoveFinished() 
        { 
        } 
 
        /// <summary> 
        /// Called when the item is added back to the river due to a timeout. 
        /// </summary> 
        internal override void Added() 
        { 
            _nextState = null; 
            if (_feedItem is ImageFeedItem) 
            { 
                _nextState = _smallImage; 
            } 
            else if (_feedItem is NewsFeedItem) 
            { 
                _nextState = _smallNews; 
            } 
            else if (_feedItem is StatusFeedItem) 
            { 
                _nextState = _smallTweet; 
            } 
 
            if (_feedItem != null && DateTime.Now - _feedItem.Date <= Settings.Default.NewItemAlert) 
            { 
                // Show the "breaking" animation for new items. 
                _breaking.Begin(this, Template, true); 
            } 
        } 
 
        #endregion 
 
        /// <summary> 
        /// When the "flash" animation completes, populate the new content and play the second half of the animation. 
        /// </summary> 
        /// <param name="sender">The source of the event.</param> 
        /// <param name="e">The <see cref="System.EventArgs"/> instance containing the event data.</param> 
        private void Flash_Completed(object sender, EventArgs e) 
        { 
            GoToState(_nextState); 
            _nextState = null; 
        } 
 
        /// <summary> 
        /// Toggle the visibility of the content renderers. 
        /// This should probably be done with VSM, but I always have trouble with it in WPF custom controls... 
        /// </summary> 
        /// <param name="state">The content renderer to show.</param> 
        private void GoToState(UserControl state) 
        { 
            _smallImage.Visibility = state == _smallImage ? Visibility.Visible : Visibility.Hidden; 
            _smallNews.Visibility = state == _smallNews ? Visibility.Visible : Visibility.Hidden; 
            _smallTweet.Visibility = state == _smallTweet ? Visibility.Visible : Visibility.Hidden; 
 
            if (state != null) 
            { 
                state.DataContext = _feedItem; 
            } 
        } 
 
        #region IsAdminTagPresent 
 
        /// <summary> 
        /// Gets or sets a value indicating whether the admin tag is present. 
        /// </summary> 
        /// <value> 
        /// <c>true</c> if the admin tag is present; otherwise, <c>false</c>. 
        /// </value> 
        public bool IsAdminTagPresent 
        { 
            get { return (bool)GetValue(IsAdminTagPresentProperty); } 
            set { SetValue(IsAdminTagPresentProperty, value); } 
        } 
 
        /// <summary> 
        /// Identifies the IsAdminTagPresent dependency property. 
        /// </summary> 
        public static readonly DependencyProperty IsAdminTagPresentProperty = DependencyProperty.Register("IsAdminTagPresent", typeof(bool), typeof(RiverContentItem), new PropertyMetadata(false)); 
 
        #endregion 
 
        /// <summary> 
        /// Handles the Click event of the admin buttons. Adds a ban to the FeedProcessor queries. 
        /// </summary> 
        /// <param name="sender">The source of the event.</param> 
        /// <param name="e">The <see cref="System.Windows.Input.RoutedEventArgs"/> instance containing the event data.</param> 
        private void AdminBtn_Click(object sender, RoutedEventArgs e) 
        { 
            if (_feedItem == null || !AppState.Instance.IsInitialized) 
            { 
                return; 
            } 
 
            if (sender == _deleteBtn) 
            { 
                AppState.Instance.AddBan(_feedItem.SourceType, string.Format(CultureInfo.InvariantCulture, "{0}", _feedItem.Uri.AbsoluteUri)); 
            } 
            else if (sender == _banBtn) 
            { 
                AppState.Instance.AddBan(_feedItem.SourceType, string.Format(CultureInfo.InvariantCulture, "{0}{1}", Processor.AuthorQueryMarker, _feedItem.Author)); 
            } 
 
            RaiseEvent(new RoutedEventArgs(RiverItemBase.RefreshRequestedEvent)); 
        } 
    } 
} 

　　

　　

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出处：http://www.cnblogs.com/flute-di/ 

转载于:https://www.cnblogs.com/flute-di/archive/2011/08/25/2153856.html