/// <summary>
/// Add an undo state to the current stage (if one is active) or directly
/// to the stack as a new stage (if one isn't).
/// </summary>
/// <param name="state"></param>
/// <param name="clearRedo">If true, the redo stack will be invalidated</param>
public void AddUndoState(UndoState state, bool clearRedo = true)
{
if (!Locked && Active)
{
if (state != null && state.IsValid)
{
if (ActiveStage != null)// && !ActiveStage.Contains(state))
{
ActiveStage.Add(state);
if (!UndoStack.Contains(ActiveStage))
{
AddUndoStage(ActiveStage);
}
}
else
{
UndoStage stage = new UndoStage();
stage.Add(state);
AddUndoStage(stage);
}
}
if (clearRedo)
{
RedoStack.Clear();
}
}
}
/// <summary>
/// Add a new stage to the redo stack
/// </summary>
/// <param name="stage"></param>
private void AddRedoStage(UndoStage stage)
{
if (stage != null && stage.Count > 0)
{
RedoStack.Add(stage);
if (RedoStack.Count > MaxStackSize)
{
RedoStack.RemoveAt(0);
}
}
}
/// <summary>
/// Redo the last redoable action
/// </summary>
public virtual void Redo()
{
Locked = true;
if (RedoStack.Count > 0)
{
UndoStage stage = RedoStack[RedoStack.Count - 1];
RedoStack.RemoveAt(RedoStack.Count - 1);
UndoStage redo = stage.Undo();
AddUndoStage(redo, false);
BeginStage();
}
Locked = false;
}
/// <summary>
/// Add a new stage to the undo stack
/// </summary>
/// <param name="stage"></param>
private void AddUndoStage(UndoStage stage, bool clearRedo = true)
{
if (stage != null && stage.Count > 0)
{
UndoStack.Add(stage);
if (UndoStack.Count > MaxStackSize)
{
UndoStack.RemoveAt(0);
}
if (clearRedo)
{
RedoStack.Clear();
}
}
}
/// <summary>
/// Revert this stage by restoring the states stored
/// within this collection
/// </summary>
/// <returns>The redo stage necessary to redo this undo.</returns>
public UndoStage Undo()
{
var redo = new UndoStage();
for (int i = Count - 1; i >= 0; i--)
{
UndoState state = this[i];
if (state.IsValid)
{
try
{
redo.Add(state.GenerateRedo());
state.Restore();
}
catch { }
}
}
return redo;
}
/// <summary>
/// Begin a new undo stage.
/// Until EndStage() is called, all undo states added will be combined together into a single MultiUndoState.
/// </summary>
/// <returns>The new MultiUndoState that represents the current stage</returns>
public UndoStage BeginStage()
{
EndStage();
ActiveStage = new UndoStage();
return(ActiveStage);
}
