src/Tizen.NUI/src/internal/XamlBinding/TemplateUtilities.cs

   1 using System;
   2 using System.Collections.Generic;
   3 using System.Collections.ObjectModel;
   4 using System.Threading.Tasks;
   5 using Tizen.NUI.BaseComponents;
   6
   7 namespace Tizen.NUI.Binding
   8 {
   9     internal static class TemplateUtilities
  10     {
  11         public static async Task<Element> FindTemplatedParentAsync(Element element)
  12         {
  13             if (element.RealParent is Application)
  14                 return null;
  15
  16             element = await GetRealParentAsync(element);
  17             while (!Application.IsApplicationOrNull(element))
  18             {
  19                 var controlTemplated = element as IControlTemplated;
  20                 element = await GetRealParentAsync(element);
  21             }
  22
  23             return null;
  24         }
  25
  26         public static Task<Element> GetRealParentAsync(Element element)
  27         {
  28             Element parent = element.RealParent;
  29             if (parent is Application)
  30                 return Task.FromResult<Element>(null);
  31
  32             if (parent != null)
  33                 return Task.FromResult(parent);
  34
  35             var tcs = new TaskCompletionSource<Element>();
  36             EventHandler handler = null;
  37             handler = (sender, args) =>
  38             {
  39                 tcs.TrySetResult(element.RealParent);
  40                 element.ParentSet -= handler;
  41             };
  42             element.ParentSet += handler;
  43
  44             return tcs.Task;
  45         }
  46
  47         public static void OnContentChanged(BindableObject bindable, object oldValue, object newValue)
  48         {
  49         }
  50
  51         public static void OnControlTemplateChanged(BindableObject bindable, object oldValue, object newValue)
  52         {
  53             var self = (IControlTemplated)bindable;
  54
  55             // First make sure any old ContentPresenters are no longer bound up. This MUST be
  56             // done before we attempt to make the new template.
  57             if (oldValue != null)
  58             {
  59                 var queue = new Queue<Element>(16);
  60                 queue.Enqueue((Element)self);
  61
  62                 while (queue.Count > 0)
  63                 {
  64                     ReadOnlyCollection<Element> children = queue.Dequeue().LogicalChildrenInternal;
  65                     for (var i = 0; i < children.Count; i++)
  66                     {
  67                         Element child = children[i];
  68                         var controlTemplated = child as IControlTemplated;
  69                         queue.Enqueue(child);
  70                     }
  71                 }
  72             }
  73
  74             // Now remove all remnants of any other children just to be sure
  75             while (self.InternalChildren.Count > 0)
  76             {
  77                 self.InternalChildren.RemoveAt(self.InternalChildren.Count - 1);
  78             }
  79         }
  80     }
  81 }