/// <summary>
/// 启动修改记录。启动之后会自动异步记录修改。
/// </summary>
/// <param name="autoCommit">是否自动提交修改？</param>
/// <returns>是否处于记录修改状态？</returns>
protected bool StartLogUndoInfo(bool autoCommit)
{
if (this.logUndoStage == LogUndoStage.NotStart)
{
// 准备空间，开始修改记录
this.logUndoStage = LogUndoStage.Logging;
this.logUndoCurrChanges = new ArrayList();
this.mapUndoCurrChanges = new Dictionary <ViDataChangedEventArgs, byte>();
// 启动异步调用，以结束 Logging
if (autoCommit)
{
this.Dispatcher.BeginInvoke(new Action(() => this.StopLogUndoInfo()),
DispatcherPriority.ApplicationIdle);
}
}
return(this.logUndoStage == LogUndoStage.Logging);
}
/// <summary>
/// 停止修改记录。
/// </summary>
protected void StopLogUndoInfo()
{
bool logChanged = false;
if (this.logUndoStage == LogUndoStage.Logging &&
this.logUndoCurrChanges.Count > 0)
{
Debug.Assert(this.logUndoCurrEditIndex >= 0 &&
this.logUndoCurrEditIndex <= this.logUndoChangesChain.Count);
// 有修改，清除后面的修改记录
if (this.logUndoCurrEditIndex < this.logUndoChangesChain.Count)
{
this.logUndoChangesChain.RemoveRange(this.logUndoCurrEditIndex,
this.logUndoChangesChain.Count - this.logUndoCurrEditIndex);
}
// 如果文件保存的位置要被丢弃了，那只能将保存位置设置为无效值了
if (this.logUndoCurrSavedIndex > this.logUndoCurrEditIndex)
{
this.logUndoCurrSavedIndex = -1;
}
LogUndoItem undoItem = new LogUndoItem(this.logUndoCurrChanges);
LogUndoItem lastItem = this.logUndoChangesChain.Count <= 0 ? null :
this.logUndoChangesChain[this.logUndoChangesChain.Count - 1] as LogUndoItem;
if (lastItem != null &&
(undoItem.ChangeType & ViChangeType.CauseDirty) == ViChangeType.None)
{ // 当前的是无关紧要的修改，合并入前一个修改项目
lastItem.ChangeType |= undoItem.ChangeType;
lastItem.Changes.AddRange(undoItem.Changes);
}
else if (lastItem != null &&
this.logUndoCurrSavedIndex < this.logUndoCurrEditIndex &&
(lastItem.ChangeType & ViChangeType.CauseDirty) == ViChangeType.None)
{ // 如果前一个是无关紧要的修改，则合并入前一个修改项目（要考虑保存位置）
lastItem.ChangeType |= undoItem.ChangeType;
lastItem.Changes.AddRange(undoItem.Changes);
}
else
{
// 将修改加入修改记录链表
this.logUndoChangesChain.Add(undoItem);
++this.logUndoCurrEditIndex;
// 修改记录不能太多，防止占用太多内存
if (this.logUndoCurrEditIndex > logUndoChainCapability)
{
// 如果文件保存的位置要被丢弃了，那只能将保存位置设置为无效值了
if (this.logUndoCurrSavedIndex == 0)
{
this.logUndoCurrSavedIndex = -1;
}
// 删除最开始的一个修改记录
this.logUndoChangesChain.RemoveAt(0);
--this.logUndoCurrEditIndex;
}
}
// LOG 内容发生了变化
logChanged = true;
}
// 恢复修改记录状态
this.logUndoStage = LogUndoStage.NotStart;
this.logUndoCurrChanges = null;
this.mapUndoCurrChanges = null;
// LOG 内容发生了变化时给出通知
if (logChanged)
{
this.NotifyContentIsChanged();
}
// 刷新各工具的状态
CommandManager.InvalidateRequerySuggested();
}
