[Silverlight入门系列]实现局部元素全屏(Element部分全屏)

本文不讨论Silverlight全屏模式的实现，有关实现这个，可以参考TerryLee的这篇文章，核心代码就是这行：

Application.Current.Host.Content.IsFullScreen = !Application.Current.Host.Content.IsFullScreen;

本文要讨论的是Silverlight的局部元素全屏，即Element部分全屏。我们在做Silverlight项目中有时候客户有这种需求：希望放大界面的局部，比如一个列表面板啥的，而不是整个界面全屏。如下图：

2011-08-19 16h14_04

实现部分全屏

实现起来也是比较简单，主要思路是用Popup实现弹出全屏，把需要全屏的元素放到容器里并设置为屏幕大小，然后整体实现全屏；当用户退出全屏的时候需要把元素恢复回原位置。好，我们写一个ElementsFullScreenProvider类，实现一个UIElement的扩展方法即可。

主要实现类：ElementsFullScreenProvider

View Code

  1 #region "Using Namespace"
  2 
  3 using System;
  4 
  5 using System.Windows;
  6 
  7 using System.Windows.Controls;
  8 
  9 using System.Windows.Controls.Primitives;
 10 
 11 #endregion
 12 
 13 namespace ElementFullScreen
 14 
 15 {
 16 
 17     /// <summary>
 18 
 19     /// Make partial UI elements full screen
 20 
 21     /// Provider features:
 22 
 23     ///    make UI element full screen
 24 
 25     ///    exit full screen and restore UI element
 26 
 27     ///    support UIElement.ToggleElementFullScreen -- extension methods
 28 
 29     /// </summary>
 30 
 31     public static class ElementsFullScreenProvider
 32 
 33     {
 34 
 35         #region Members
 36 
 37         static readonly Popup PopupContainer;
 38 
 39         static readonly Panel PopupContentContainer;
 40 
 41         static ElementController _lastElementController; 
 42 
 43         #endregion
 44 
 45         #region ElementController
 46 
 47         class ElementController
 48 
 49         {
 50 
 51             double _height = double.NaN;
 52 
 53             double _width = double.NaN;
 54 
 55             int _lastPanelPosition;
 56 
 57             bool _lastPopupIsOpen;
 58 
 59             readonly DependencyObject _parent;
 60 
 61             Thickness? _margin;
 62 
 63             public UIElement Element { get; private set; }
 64 
 65             public ElementController(UIElement element)
 66 
 67             {
 68 
 69                 Element = element;
 70 
 71                 var elem = element as FrameworkElement;
 72 
 73                 if (elem != null && elem.Parent != null)
 74 
 75                 {
 76 
 77                     _parent = elem.Parent;
 78 
 79                 }
 80 
 81             }
 82 
 83             public void BringElementToFullScreen()
 84 
 85             {
 86 
 87                 TryAction<frameworkelement>(Element, f =>
 88 
 89                 {
 90 
 91                     _height = f.Height;
 92 
 93                     _width = f.Width;
 94 
 95                     f.Height = double.NaN;
 96 
 97                     f.Width = double.NaN;
 98 
 99                 });
100 
101                 TryAction<control>(Element, f =>
102 
103                 {
104 
105                     _margin = f.Margin;
106 
107                     f.Margin = new Thickness(0);
108 
109                 });
110 
111                 if (_parent != null)
112 
113                 {
114 
115                     if (!TryAction<panel>(_parent, p => { _lastPanelPosition = p.Children.IndexOf(Element); p.Children.RemoveAt(_lastPanelPosition); }))
116 
117                         if (!TryAction<contentcontrol>(_parent, c => c.Content = null))
118 
119                             if (!TryAction<usercontrol>(_parent, u => u.Content = null))
120 
121                                 TryAction<popup>(_parent, p => { _lastPopupIsOpen = p.IsOpen; p.Child = null; });
122 
123                 }
124 
125             }
126 
127             public void ReturnElementFromFullScreen()
128 
129             {
130 
131                 TryAction<frameworkelement>(Element, f =>
132 
133                 {
134 
135                     f.Height = _height;
136 
137                     f.Width = _width;
138 
139                 });
140 
141                 TryAction<control>(Element, f =>
142 
143                 {
144 
145                     if (_margin.HasValue)
146 
147                     {
148 
149                         f.Margin = _margin.Value;
150 
151                     }
152 
153                 });
154 
155                 if (_parent != null)
156 
157                 {
158 
159                     if (!TryAction<panel>(_parent, p => p.Children.Insert(_lastPanelPosition, Element)))
160 
161                         if (!TryAction<contentcontrol>(_parent, c => c.Content = Element))
162 
163                             if (!TryAction<usercontrol>(_parent, u => u.Content = Element))
164 
165                                 TryAction<popup>(_parent, p => { p.Child = Element; p.IsOpen = _lastPopupIsOpen; });
166 
167                 }
168 
169             }
170 
171             static bool TryAction<t>(object o, Action<t> action)
172 
173                 where T : class
174 
175             {
176 
177                 T val = o as T;
178 
179                 if (val != null)
180 
181                 {
182 
183                     action(val);
184 
185                     return true;
186 
187                 }
188 
189                 return false;
190 
191             }
192 
193         }
194 
195         #endregion
196 
197         #region FullscreenElementID Attached Property
198 
199         static readonly DependencyProperty FullscreenElementIDProperty = DependencyProperty.RegisterAttached(
200 
201            "FullscreenElementID", typeof(Guid?), typeof(ElementsFullScreenProvider), new PropertyMetadata(null));
202 
203         static void SetFullscreenElementID(DependencyObject obj, Guid? value)
204 
205         {
206 
207             obj.SetValue(FullscreenElementIDProperty, value);
208 
209         }
210 
211         static Guid? GetFullscreenElementID(DependencyObject obj)
212 
213         {
214 
215             return (Guid?)obj.GetValue(FullscreenElementIDProperty);
216 
217         }
218 
219         #endregion
220 
221         #region Initialization
222 
223         /// <summary>
224 
225         /// Initializes the <see cref="ElementsFullScreenProvider"> class.
226 
227         /// </see></summary>
228 
229         static ElementsFullScreenProvider()
230 
231         {
232 
233             PopupContentContainer = new Grid();
234 
235             PopupContainer = new Popup
236 
237             {
238 
239                 Child = PopupContentContainer
240 
241             };
242 
243             Application.Current.Host.Content.FullScreenChanged += delegate
244 
245             {
246 
247                 if (_lastElementController == null) return;
248 
249                 if (!Application.Current.Host.Content.IsFullScreen)
250 
251                 {
252 
253                     ReturnElementFromFullScreen();
254 
255                 }
256 
257                 else
258 
259                 {
260 
261                     UpdateContentSize();
262 
263                 }
264 
265             };
266 
267         } 
268 
269         #endregion
270 
271         #region Public Methods
272 
273         public static void BringElementToFullScreen(this UIElement element)
274 
275         {
276 
277             if (_lastElementController == null)
278 
279             {
280 
281                 _lastElementController = new ElementController(element);
282 
283                 _lastElementController.BringElementToFullScreen();
284 
285                 PopupContentContainer.Children.Add(element);
286 
287                 PopupContainer.IsOpen = true;
288 
289             }
290 
291         }
292 
293         public static void ReturnElementFromFullScreen(this UIElement element)
294 
295         {
296 
297             ReturnElementFromFullScreen();
298 
299         }
300 
301         public static void ReturnElementFromFullScreen()
302 
303         {
304 
305             if (_lastElementController != null)
306 
307             {
308 
309                 PopupContentContainer.Children.Clear();
310 
311                 _lastElementController.ReturnElementFromFullScreen();
312 
313                 PopupContainer.IsOpen = false;
314 
315                 _lastElementController = null;
316 
317             }
318 
319         }
320 
321         public static void ToggleElementFullScreen(this UIElement element)
322 
323         {
324 
325             bool newValue = !Application.Current.Host.Content.IsFullScreen;
326 
327             bool toggle = false;
328 
329             if (newValue)
330 
331             {
332 
333                 if (_lastElementController == null)
334 
335                 {
336 
337                     element.BringElementToFullScreen();
338 
339                     toggle = true;
340 
341                 }
342 
343             }
344 
345             else
346 
347             {
348 
349                 if (_lastElementController != null && ReferenceEquals(element, _lastElementController.Element))
350 
351                 {
352 
353                     element.ReturnElementFromFullScreen();
354 
355                     toggle = true;
356 
357                 }
358 
359             }
360 
361             if (toggle)
362 
363             {
364 
365                 ToggleFullScreen();
366 
367             }
368 
369         }
370 
371         public static void ToggleFullScreen()
372 
373         {
374 
375             Application.Current.Host.Content.IsFullScreen = !Application.Current.Host.Content.IsFullScreen;
376 
377         }
378 
379         #endregion
380 
381         #region Private Method
382 
383         private static void UpdateContentSize()
384 
385         {
386 
387             if (Application.Current != null && Application.Current.Host != null && Application.Current.Host.Content != null)
388 
389             {
390 
391                 double height = Application.Current.Host.Content.ActualHeight;
392 
393                 double width = Application.Current.Host.Content.ActualWidth;
394 
395                 //if (Application.Current.Host.Settings.EnableAutoZoom)
396 
397                 //{
398 
399                 //    double zoomFactor = Application.Current.Host.Content.ZoomFactor;
400 
401                 //    if (zoomFactor != 0.0)
402 
403                 //    {
404 
405                 //        height /= zoomFactor;
406 
407                 //        width /= zoomFactor;
408 
409                 //    }
410 
411                 //}
412 
413                 PopupContentContainer.Height = height;
414 
415                 PopupContentContainer.Width = width;
416 
417             }
418 
419         } 
420 
421         #endregion
422 
423     }
424 
425 }

调用的时候使用UIElement的扩展方法实现全屏：

 1: private void button1_Click(object sender, RoutedEventArgs e)

 2: {

 3:  SilverArea/*你希望全屏的元素*/.ToggleElementFullScreen();//调用UIElement的扩展方法

 4:  }

本文源码下载请点击此处。主要就一个类ElementsFullScreenProvider.cs，用起来就一个函数ToggleElementFullScreen()，简单之极。

说明：本文出处：http://www.cnblogs.com/Mainz/archive/2011/08/19/2145933.html

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原文地址：https://www.cnblogs.com/zxbzl/p/2949848.html