internal ItemsChangedEventArgs (NotifyCollectionChangedAction action, int itemCount, int itemUICount, GeneratorPosition oldPosition, GeneratorPosition position)
{
this.action = action;
item_count = itemCount;
item_ui_count = itemUICount;
old_position = oldPosition;
this.position = position;
}
private void CleanUpItems(int firstIndex, int lastIndex)
{
for (int i = InternalChildren.Count - 1; i >= 0; i--)
{
var childGeneratorPos = new GeneratorPosition(i, 0);
int itemIndex = generator.IndexFromGeneratorPosition(childGeneratorPos);
if ((itemIndex < firstIndex || itemIndex > lastIndex) && itemIndex > 0)
{
generator.Remove(childGeneratorPos, 1);
RemoveInternalChildRange(i, 1);
}
}
}
internal void Recycle(GeneratorPosition position, int count)
{
this.CheckOffsetAndRealized(position, count);
int index = this.IndexFromGeneratorPosition(position);
for (int i = 0; i < count; i++)
{
this.Cache.Enqueue(this.ContainerIndexMap[index + i]);
}
this.Remove(position, count);
}
public void CleanUpItems(int minDesiredGenerated, int maxDesiredGenerated)
{
for (int i = this._children.Count - 1; i >= 0; i--)
{
GeneratorPosition childGeneratorPos = new GeneratorPosition(i, 0);
int itemIndex = this._generator.IndexFromGeneratorPosition(childGeneratorPos);
if (itemIndex < minDesiredGenerated || itemIndex > maxDesiredGenerated)
{
this._generator.Remove(childGeneratorPos, 1);
this.RemoveInternalChildRange(i, 1);
}
}
}
/// <summary>
/// Removes items that are outside the desired positions</summary>
/// <param name="minDesiredGenerated">Minimum desired generator position</param>
/// <param name="maxDesiredGenerated">Maximum desired generator position</param>
protected void CleanUpItems(int minDesiredGenerated, int maxDesiredGenerated)
{
for (int i = m_children.Count - 1; i >= 0; i--)
{
var childGeneratorPos = new GeneratorPosition(i, 0);
int itemIndex = m_generator.IndexFromGeneratorPosition(childGeneratorPos);
if (itemIndex < minDesiredGenerated || itemIndex > maxDesiredGenerated)
{
m_generator.Remove(childGeneratorPos, 1);
RemoveInternalChildRange(i, 1);
}
}
}
/// <summary>
/// Revirtualizes the items that are no longer visible.
/// </summary>
/// <param name="minDesiredGenerated">The first item index that should be visible.</param>
/// <param name="maxDesiredGenerated">The last item index that should be visible.</param>
private void CleanUpItems(int minDesiredGenerated, int maxDesiredGenerated)
{
for (int i = InternalChildren.Count - 1; i >= 0; i--)
{
GeneratorPosition childPos = new GeneratorPosition(i, 0);
int itemIndex = ItemContainerGenerator.IndexFromGeneratorPosition(childPos);
if (itemIndex < minDesiredGenerated || itemIndex > maxDesiredGenerated)
{
ItemContainerGenerator.Remove(childPos, 1);
RemoveInternalChildRange(i, 1);
}
}
}
void GenerateItemContainers()
{
IItemContainerGenerator generator = ItemContainerGenerator;
GeneratorPosition position = generator.GeneratorPositionFromIndex(0);
using (generator.StartAt(position, GeneratorDirection.Forward, true))
{
foreach (object o in Items)
{
DependencyObject dp = generator.GenerateNext();
generator.PrepareItemContainer(dp);
}
}
}
void RemoveItemsFromPresenter(GeneratorPosition position, int count)
{
if (_presenter == null || _presenter._elementRoot == null || _presenter._elementRoot is VirtualizingPanel)
{
return;
}
Panel panel = _presenter._elementRoot;
while (count-- > 0)
{
panel.Children.RemoveAt(position.Index);
}
}
public void GeneratorPositionFromIndex_OutOfRange_TwoElements_Realised()
{
Control.Items.Add(new object());
Control.Items.Add(new object());
CreateAsyncTest(Control,
() => Control.ApplyTemplate(),
() => {
GeneratorPosition p = Generator.GeneratorPositionFromIndex(100);
Assert.AreEqual(-1, p.Index, "#1");
Assert.AreEqual(0, p.Offset, "#2");
}
);
}
private void RealizeFirstItem()
{
IItemContainerGenerator generator = ItemContainerGenerator;
GeneratorPosition pos = generator.GeneratorPositionFromIndex(0);
using (generator.StartAt(pos, GeneratorDirection.Forward))
{
var element = generator.GenerateNext() as UIElement;
generator.PrepareItemContainer(element);
AddInternalChild(element);
}
}
void GenerateForwardFromMiddle()
{
//<SnippetGenerateForwardFromMiddleCODE>
// Start generating items forward,
// starting with the first unrealized item (offset of 1),
// after the 5th realized item
// (the item with index 4 among all realized items) in the list
GeneratorPosition position = new GeneratorPosition(4, 1);
GeneratorDirection direction = GeneratorDirection.Forward;
IItemContainerGenerator generator = (IItemContainerGenerator)this.itemsControl.ItemContainerGenerator;
generator.StartAt(position, direction);
//</SnippetGenerateForwardFromMiddleCODE>
}
private void MeasureCore()
{
// 注意，在第一次使用 ItemContainerGenerator之前要先访问一下InternalChildren,
// 否则ItemContainerGenerator为null，是一个Bug
UIElementCollection children = InternalChildren;
IItemContainerGenerator generator = ItemContainerGenerator;
if (generator != null)
{
// 获取第一个可视元素位置信息
GeneratorPosition position = generator.GeneratorPositionFromIndex(this._startIndex);
// 根据元素位置信息计算子元素索引
int childIndex = position.Offset == 0 ? position.Index : position.Index + 1;
using (generator.StartAt(position, GeneratorDirection.Forward, true))
{
for (int itemIndex = this._startIndex; itemIndex <= this._endIndex; itemIndex++, childIndex++)
{
bool isNewlyRealized; // 用以指示新生成的元素是否是新实体化的
// 生成下一个子元素
var child = (UIElement)generator.GenerateNext(out isNewlyRealized);
if (child == null)
{
break;
}
if (isNewlyRealized)
{
if (childIndex >= children.Count)
{
AddInternalChild(child);
}
else
{
InsertInternalChild(childIndex, child);
}
generator.PrepareItemContainer(child);
}
// 测算子元素布局
child.Measure(this._eachSize);
}
}
}
this.CleanUpItems(this._startIndex, this._endIndex);
}
/// <summary>
/// scroll/availableSize/添加删除元素 改变都会触发 edit元素不会改变
/// </summary>
/// <param name="availableSize"></param>
/// <returns></returns>
protected override Size MeasureOverride(Size availableSize)
{
this.UpdateScrollInfo(availableSize);//availableSize更新后，更新滚动条
int firstVisiableIndex = 0, lastVisiableIndex = 0;
GetVisiableRange(ref firstVisiableIndex, ref lastVisiableIndex); //availableSize更新后，获取当前viewport内可放置的item的开始和结束索引 firstIdnex-lastIndex之间的item可能部分在viewport中也可能都不在viewport中。
UIElementCollection children = this.InternalChildren; //因为配置了虚拟化，所以children的个数一直是viewport区域内的个数,如果没有虚拟化则是ItemSource的整个的个数
IItemContainerGenerator generator = this.ItemContainerGenerator;
//获得第一个可被显示的item的位置
GeneratorPosition startPosi = generator.GeneratorPositionFromIndex(firstVisiableIndex);
int childIndex = (startPosi.Offset == 0) ? startPosi.Index : startPosi.Index + 1;//startPosi在chilren中的索引
using (generator.StartAt(startPosi, GeneratorDirection.Forward, true))
{
int itemIndex = firstVisiableIndex;
while (itemIndex <= lastVisiableIndex)//生成lastVisiableIndex-firstVisiableIndex个item
{
bool newlyRealized = false;
var child = generator.GenerateNext(out newlyRealized) as UIElement;
if (newlyRealized)
{
if (childIndex >= children.Count)
{
base.AddInternalChild(child);
}
else
{
base.InsertInternalChild(childIndex, child);
}
generator.PrepareItemContainer(child);
}
else
{
//处理 正在显示的child被移除了这种情况
if (!child.Equals(children[childIndex]))
{
base.RemoveInternalChildRange(childIndex, 1);
}
}
child.Measure(new Size(this.ChildWidth, this.ChildHeight));
//child.DesiredSize//child想要的size
itemIndex++;
childIndex++;
}
}
CleanUpItems(firstVisiableIndex, lastVisiableIndex);
return(new Size(double.IsInfinity(availableSize.Width) ? 0 : availableSize.Width, double.IsInfinity(availableSize.Height) ? 0 : availableSize.Height));//自身想要的size
}
public void VirtualizeItem(int itemIndex)
{
IItemContainerGenerator itemContainerGenerator = base.ItemContainerGenerator;
if (itemContainerGenerator != null)
{
GeneratorPosition position = itemContainerGenerator.GeneratorPositionFromIndex(itemIndex);
if (position.Offset == 0)
{
itemContainerGenerator.Remove(position, 1);
base.InternalChildren[position.Index].ClearValue(IndexForItemContainerProperty);
RemoveInternalChildRange(position.Index, 1);
}
}
}
public void CleanUp(int minDesiredGenerated, int maxDesiredGenerated)
{
int internalChildrenCount = _panel.getInternalChildren().Count;
for (int i = internalChildrenCount - 1; i >= 0; i--)
{
GeneratorPosition childGeneratorPos = new GeneratorPosition(i, 0);
int itemIndex = _generator.IndexFromGeneratorPosition(childGeneratorPos);
if (itemIndex < minDesiredGenerated || itemIndex > maxDesiredGenerated)
{
_generator.Remove(childGeneratorPos, 1);
_panel.removeInternalChild(i);
}
}
}
private void CleanupItems()
{
IItemContainerGenerator generator = _itemsOwner.ItemContainerGenerator;
for (int i = InternalChildren.Count - 1; i >= 0; i--)
{
var position = new GeneratorPosition(i, 0);
int itemIndex = generator.IndexFromGeneratorPosition(position);
if (itemIndex < _startIndex || itemIndex > _endIndex)
{
generator.Remove(position, 1);
RemoveInternalChildRange(i, 1);
}
}
}
private UIElement ForceContainerGeneration(object item)
{
int itemIndex = IndexOf(item);
UIElement container = null;
bool isNewlyRealized = false;
IItemContainerGenerator generator = dataGrid.ItemContainerGenerator;
GeneratorPosition gp = generator.GeneratorPositionFromIndex(itemIndex);
using (generator.StartAt(gp, GeneratorDirection.Forward, true))
{
isNewlyRealized = false;
container = generator.GenerateNext(out isNewlyRealized) as UIElement;
}
return(container);
}
private void CleanUpChildren(int minIndex, int maxIndex)
{
UIElementCollection children = base.Children;
IItemContainerGenerator generator = base.ItemContainerGenerator;
for (int i = children.Count - 1; i >= 0; i--)
{
GeneratorPosition pos = new GeneratorPosition(i, 0);
int itemIndex = generator.IndexFromGeneratorPosition(pos);
if (itemIndex < minIndex || itemIndex > maxIndex)
{
generator.Remove(pos, 1);
base.RemoveInternalChildRange(i, 1);
}
}
}
private void CleanUpChildren(int minIndex, int maxIndex)
{
var children = this.Children;
var generator = this.ItemContainerGenerator;
for (var i = children.Count - 1; i >= 0; i--)
{
var pos = new GeneratorPosition(i, 0);
var itemIndex = generator.IndexFromGeneratorPosition(pos);
if (itemIndex < minIndex || itemIndex > maxIndex)
{
generator.Remove(pos, 1);
RemoveInternalChildRange(i, 1);
}
}
}
void CheckOffsetAndRealized(GeneratorPosition position, int count)
{
if (position.Offset != 0)
{
throw new ArgumentException("position.Offset must be zero as the position must refer to a realized element");
}
int index = IndexFromGeneratorPosition(position);
int rangeIndex = RealizedElements.FindRangeIndexForValue(index);
RangeCollection.Range range = RealizedElements.Ranges[rangeIndex];
if (index < range.Start || (index + count) > range.Start + range.Count)
{
throw new InvalidOperationException("Only items which have been Realized can be removed");
}
}
internal void Remove(GeneratorPosition position, int count)
{
this.CheckOffsetAndRealized(position, count);
int index = this.IndexFromGeneratorPosition(position);
for (int i = 0; i < count; i++)
{
var container = this.ContainerIndexMap[index + i];
var item = this.ContainerItemMap[container];
this.ContainerIndexMap.Remove(container, index + i);
this.ContainerItemMap.Remove(container);
this.RealizedElements.Remove(index + i);
this.Owner.ClearContainerForItem(container, item);
}
}
void TestAnalyzers()
{
PropertyChangedEventArgs changeArgs = new PropertyChangedEventArgs("tstProp");
ObservableCollection <string> c = new ObservableCollection <string>(); //Cannot run in try-convert
var cornerRadius1 = new CornerRadius(2);
var cornerRadius2 = new CornerRadius(1, 2, 3, 4);
var duration = new Duration(new TimeSpan(33));
var gridLength1 = new GridLength(12);
var gridLength2 = new GridLength(1, GridUnitType.Pixel);
var thickness1 = new Thickness(2);
var thickness2 = new Thickness(2, 3, 4, 5);
var generatorPosition = new GeneratorPosition(23, 123);
var matrix = new Matrix(6, 5, 4, 3, 2, 1);
var repeatBehavior1 = new RepeatBehavior(12);
var repeatBehavior2 = new RepeatBehavior(new TimeSpan(10));
}
private void CleanUpItems(int minDesiredGenerated, int maxDesiredGenerated)
{
UIElementCollection internalChildren = base.InternalChildren;
IItemContainerGenerator itemContainerGenerator = base.ItemContainerGenerator;
for (int i = internalChildren.Count - 1; i >= 0; i--)
{
GeneratorPosition position = new GeneratorPosition(i, 0);
int num2 = itemContainerGenerator.IndexFromGeneratorPosition(position);
if ((num2 < minDesiredGenerated) || (num2 > maxDesiredGenerated))
{
itemContainerGenerator.Remove(position, 1);
base.RemoveInternalChildRange(i, 1);
}
}
}
/// <summary>
/// Revirtualize items that are no longer visible
/// </summary>
/// <param name="minDesiredGenerated">first item index that should be visible</param>
/// <param name="maxDesiredGenerated">last item index that should be visible</param>
private void CleanUpItems(int minDesiredGenerated, int maxDesiredGenerated)
{
var children = InternalChildren;
var generator = ItemContainerGenerator;
for (var i = children.Count - 1; i >= 0; i--)
{
var childGeneratorPos = new GeneratorPosition(i, 0);
var itemIndex = generator.IndexFromGeneratorPosition(childGeneratorPos);
if (itemIndex < minDesiredGenerated || itemIndex > maxDesiredGenerated)
{
generator.Remove(childGeneratorPos, 1);
RemoveInternalChildRange(i, 1);
}
}
}
private void RemoveItemsFromPresenter(GeneratorPosition position, int count)
{
if (this.itemsPresenter == null ||
this.itemsPresenter.Child == null ||
this.itemsPresenter.Child is VirtualizingPanel)
{
return;
}
Panel panel = this.itemsPresenter.Child;
while (count-- > 0)
{
panel.InternalChildren.RemoveAt(position.Index);
}
}
/// <summary>
/// Revirtualize items that are no longer visible
/// </summary>
/// <param name="minDesiredGenerated">first item index that should be visible</param>
/// <param name="maxDesiredGenerated">last item index that should be visible</param>
private void CleanUpItems(int minDesiredGenerated, int maxDesiredGenerated)
{
UIElementCollection children = this.InternalChildren;
IItemContainerGenerator generator = this.ItemContainerGenerator;
for (int i = children.Count - 1; i >= 0; i--)
{
GeneratorPosition childGeneratorPos = new GeneratorPosition(i, 0);
int itemIndex = generator.IndexFromGeneratorPosition(childGeneratorPos);
if (itemIndex < minDesiredGenerated || itemIndex > maxDesiredGenerated)
{
generator.Remove(childGeneratorPos, 1);
RemoveInternalChildRange(i, 1);
}
}
}
private void Button_Click(object sender, RoutedEventArgs e)
{
var value1 = dg.ItemContainerGenerator.ContainerFromIndex(30);
UIElement cntr = null;
bool isNewlyRealized = false;
IItemContainerGenerator generator = dg.ItemContainerGenerator;
GeneratorPosition gp = generator.GeneratorPositionFromIndex(30);
using (generator.StartAt(gp, GeneratorDirection.Forward, true))
{
isNewlyRealized = false;
cntr = generator.GenerateNext(out isNewlyRealized) as UIElement;
}
MessageBox.Show("Row 30: " + value1 + ", " + cntr + ", " + isNewlyRealized);
}
private void CleanUpItems(int minDesiredGenerated, int maxDesiredGenerated)
{
for (var i = _children.Count - 1; i >= 0; i--)
{
var childGeneratorPos = new GeneratorPosition(i, 0);
var itemIndex = _generator.IndexFromGeneratorPosition(childGeneratorPos);
if (itemIndex < minDesiredGenerated || itemIndex > maxDesiredGenerated)
{
if (itemIndex >= 0)
{
_generator.Remove(childGeneratorPos, 1);
}
RemoveInternalChildRange(i, 1);
}
}
}
/// <summary>
/// <see cref="System.Windows.Media.Visual"/> オブジェクトの座標空間が表示されるまで、
/// コンテンツを強制的にスクロールする。
/// </summary>
/// <param name="visual">表示可能になる <see cref="System.Windows.Media.Visual"/>。</param>
/// <param name="rectangle">表示する座標空間を識別する外接する四角形。</param>
/// <returns>表示される <see cref="System.Windows.Rect"/>。</returns>
public Rect MakeVisible(Visual visual, Rect rectangle)
{
var idx = this.InternalChildren.IndexOf(visual as UIElement);
var generator = this.ItemContainerGenerator as IItemContainerGenerator;
if (generator != null)
{
var pos = new GeneratorPosition(idx, 0);
idx = generator.IndexFromGeneratorPosition(pos);
}
if (idx < 0)
{
return(Rect.Empty);
}
if (!this.containerLayouts.ContainsKey(idx))
{
return(Rect.Empty);
}
var layout = this.containerLayouts[idx];
if (this.HorizontalOffset + this.ViewportWidth < layout.X + layout.Width)
{
this.SetHorizontalOffset(layout.X + layout.Width - this.ViewportWidth);
}
if (layout.X < this.HorizontalOffset)
{
this.SetHorizontalOffset(layout.X);
}
if (this.VerticalOffset + this.ViewportHeight < layout.Y + layout.Height)
{
this.SetVerticalOffset(layout.Y + layout.Height - this.ViewportHeight);
}
if (layout.Y < this.VerticalOffset)
{
this.SetVerticalOffset(layout.Y);
}
layout.Width = Math.Min(this.ViewportWidth, layout.Width);
layout.Height = Math.Min(this.ViewportHeight, layout.Height);
return(layout);
}
/// <summary>
/// 清除不显示的单元格。
/// </summary>
/// <param name="children"></param>
/// <param name="generator"></param>
private void Cleanup(UIElementCollection children, IItemContainerGenerator generator)
{
//清除不需要显示的子元素，注意从集合后向前操作，以免造成操作过程中元素索引发生改变
for (int i = children.Count - 1; i > -1; i--)
{
// 通过已显示的子元素的位置信息得出元素索引
var childGeneratorPos = new GeneratorPosition(i, 0);
int itemIndex = generator.IndexFromGeneratorPosition(childGeneratorPos);
// 移除不再显示的元素
if (itemIndex < this._from || itemIndex > this._to)
{
generator.Remove(childGeneratorPos, 1);
this.RemoveInternalChildRange(i, 1);
}
}
}
private void CleanUpItems(int minDesiredGenerated, int maxDesiredGenerated)
{
var internalChildren = InternalChildren;
var itemContainerGenerator = ItemContainerGenerator;
for (var i = internalChildren.Count - 1; i >= 0; i--)
{
var position = new GeneratorPosition(i, 0);
var num2 = itemContainerGenerator.IndexFromGeneratorPosition(position);
if ((num2 >= minDesiredGenerated) && (num2 <= maxDesiredGenerated))
{
continue;
}
itemContainerGenerator.Remove(position, 1);
RemoveInternalChildRange(i, 1);
}
}
void IItemContainerGenerator.Remove (GeneratorPosition position, int count)
{
throw new Exception ("The method or operation is not implemented.");
}
int IItemContainerGenerator.IndexFromGeneratorPosition (GeneratorPosition position)
{
throw new Exception ("The method or operation is not implemented.");
}
IDisposable IItemContainerGenerator.StartAt (GeneratorPosition position, GeneratorDirection direction, bool allowStartAtRealizedItem)
{
throw new Exception ("The method or operation is not implemented.");
}
