/// <summary>
/// Ends a batch of undoable operations.
/// </summary>
/// <param name="rollback">Set to true if the batch needs to be undone immediately.</param>
/// <returns></returns>
public int EndBatch(bool rollback = false)
{
if (!Enabled)
{
return(0);
}
if (inProgress)
{
return(0);
}
if (batchDepth == 0)
{
throw new InvalidOperationException("EndBatch() called before BeginBatch().");
}
batchDepth--;
if ((_UndoStack.Peek() as UndoBatchAction)?.Begin ?? false)
{
// If the last action on the stack is a begin-BatchAction, it means no actions was performed
// in this batch. Pop the last BatchAction to avoid having an empty batch on the stack.
var a = _UndoStack.Pop() as UndoBatchAction;
if (!a.Begin)
{
throw new InvalidOperationException(); // should not happen
}
return(0);
}
else if ((_UndoStack.Skip(1).FirstOrDefault() as UndoBatchAction)?.Begin ?? false)
{
// If the batch action only contains a single non-batch action, we might as well pop the batch
// and add the non-batch action directly to the stack:
var a = _UndoStack.Pop();
var beginBatch = _UndoStack.Pop();
_UndoStack.Push(a);
}
else
{
var actionName = _UndoStack.OfType <UndoBatchAction>().First(uba => uba.Depth == batchDepth).ActionName;
_UndoStack.Push(new UndoBatchAction(actionName, batchDepth, false));
}
// Rollback if requested:
if (rollback)
{
XDo(false, false);
return(0);
}
UndoStateChanged?.Invoke(this, new EventArgs());
return(batchSizeCounter);
}
/// <summary>
/// Call this method when an action is performed, that should be undoable
/// </summary>
/// <param name="action"></param>
internal void Add(IUndoAction action)
{
if (!Enabled)
{
return;
}
if (inProgress)
{
return;
}
_UndoStack.Push(action);
if (CanRedo)
{
_RedoStack.Clear();
}
batchSizeCounter++;
if (!(action is UndoBatchAction) && batchDepth == 0)
{
UndoStateChanged?.Invoke(this, new EventArgs());
}
}
internal void XDo(bool redo, bool inversable)
{
if (!Enabled)
{
throw new InvalidOperationException("UndoManager is not enabled.");
}
//if (undoDepth == -1 && batchDepth != 0) throw new InvalidOperationException("Cannot undo/redo while a batch is in progress.");
_handler.BeginUpdate(null);
var stack = redo ? _RedoStack : _UndoStack;
var inverseStack = redo ? _UndoStack : _RedoStack;
if (stack.Count > 0)
{
inProgress = true;
IsRedoing = redo;
IsUndoing = !IsRedoing;
var item = stack.Pop();
if (redo)
{
item.Redo();
}
else
{
item.Undo();
}
if (inversable)
{
inverseStack.Push(item);
}
if (item is UndoBatchAction)
{
var batchDepth = (item as UndoBatchAction).Depth;
do
{
item = stack.Pop();
if (redo)
{
item.Redo();
}
else
{
item.Undo();
}
if (inversable)
{
inverseStack.Push(item);
}
}while (!(item is UndoBatchAction) || (item as UndoBatchAction).Depth > batchDepth);
}
IsRedoing = false;
IsUndoing = false;
inProgress = false;
}
UndoStateChanged?.Invoke(this, new EventArgs());
_handler.EndUpdate(false);
}
