/// <summary>
/// Adds a unit to the undo manager without executing it
/// </summary>
/// <param name="unit">The UndoUnit to add</param>
void Add(UndoUnit <T> unit)
{
if (IsBlocked)
{
throw new InvalidOperationException("Attempt to add undo operation while blocked");
}
if (CurrentGroup != null)
{
CurrentGroup.Add(unit);
}
else
{
RemoveAllRedoUnits();
_units.Add(unit);
// Limit undo stack size
if (_units.Count > _maxUnits)
{
// Update unmodified index
if (_unmodifiedPos >= 0)
{
_unmodifiedPos--;
}
// Remove
_units.RemoveAt(0);
}
else
{
_currentPos++;
}
}
}
/// <summary>
/// Execute an undo unit and add it to the manager
/// </summary>
/// <param name="unit">The undo unit to execute</param>
public void Do(UndoUnit <T> unit)
{
// Only if not blocked
if (IsBlocked)
{
throw new InvalidOperationException("Attempt to execute undo operation while blocked");
}
// Fire start
if (CurrentGroup == null)
{
OnStartOperation();
}
// Remember if was modified
bool wasModified = IsModified;
try
{
// Do it
unit.Do(_context);
Add(unit);
}
finally
{
// End operation if not in a group
if (CurrentGroup == null)
{
OnEndOperation();
}
// Fire modified changed
if (wasModified != IsModified)
{
OnModifiedChanged();
}
}
}
/// <summary>
/// Inserts an unit to this group
/// </summary>
/// <param name="position">The position at which the unit should be inserted</param>
/// <param name="unit">The UndoUnit to be inserted</param>
public void Insert(int position, UndoUnit <T> unit)
{
unit.Group = this;
_units.Insert(position, unit);
}
/// <summary>
/// Adds a unit to this group
/// </summary>
/// <param name="unit">The UndoUnit to be added</param>
public void Add(UndoUnit <T> unit)
{
unit.Group = this;
_units.Add(unit);
}