/// <summary>
/// Calls <see cref="UndoableCommand.Unexecute"/> in order to 'undo' the current command.
/// </summary>
/// <remarks>
/// Decrements the <see cref="CurrentCommandIndex"/>, unless it is already -1. A <see cref="CurrentCommandIndex"/> of -1
/// indicates that the entire command history has been undone and only <see cref="Redo"/> operations can occur.
/// </remarks>
public void Undo()
{
if (NumCommands == 0)
{
return;
}
if (_currentCommandIndex == -1)
{
return;
}
EventsHelper.Fire(_currentCommandChangingEvent, this, EventArgs.Empty);
UndoableCommand cmd = _history[_currentCommandIndex];
try
{
cmd.Unexecute();
}
catch (Exception e)
{
Platform.Log(LogLevel.Error, e);
}
_currentCommandIndex--;
EventsHelper.Fire(_currentCommandChangedEvent, this, EventArgs.Empty);
}
/// <summary>
/// Adds a command to the command history.
/// </summary>
/// <remarks>
/// When a command is added, all commands after the <see cref="CurrentCommandIndex"/> will be removed
/// in order to keep the state of the application consistent. The added command will then become
/// the last command (<see cref="LastCommandIndex"/>).
/// </remarks>
public void AddCommand(UndoableCommand command)
{
Platform.CheckForNullReference(command, "command");
EventsHelper.Fire(_currentCommandChangingEvent, this, EventArgs.Empty);
if (_currentCommandIndex < _lastCommandIndex)
{
int numCommandsToRemove = _lastCommandIndex - _currentCommandIndex;
_history.RemoveRange(_currentCommandIndex + 1, numCommandsToRemove);
_lastCommandIndex -= numCommandsToRemove;
}
_history.Add(command);
if (NumCommands > _maxSize)
{
_history.RemoveAt(0);
if (_currentCommandIndex == _lastCommandIndex)
{
_currentCommandIndex--;
}
_lastCommandIndex--;
}
_currentCommandIndex++;
_lastCommandIndex++;
EventsHelper.Fire(_currentCommandChangedEvent, this, EventArgs.Empty);
}
//private bool _isCurrent = false;
private CommandInfo(UndoableCommand command)
{
_name = command.Name;
_hashcode = command.GetHashCode();
Type type = command.GetType();
_type = type.FullName;
_assembly = type.Assembly.FullName;
}
/// <summary>
/// Adds/Enqueues an <see cref="UndoableCommand"/>.
/// </summary>
public void Enqueue(UndoableCommand command)
{
_commands.Add(command);
}
/// <summary>
/// Adds/Enqueues an <see cref="UndoableCommand"/>.
/// </summary>
public void Enqueue(UndoableCommand command)
{
_commands.Add(command);
}
/// <summary>
/// Adds a command to the command history.
/// </summary>
/// <remarks>
/// When a command is added, all commands after the <see cref="CurrentCommandIndex"/> will be removed
/// in order to keep the state of the application consistent. The added command will then become
/// the last command (<see cref="LastCommandIndex"/>).
/// </remarks>
public void AddCommand(UndoableCommand command)
{
Platform.CheckForNullReference(command, "command");
EventsHelper.Fire(_currentCommandChangingEvent, this, EventArgs.Empty);
if (_currentCommandIndex < _lastCommandIndex)
{
int numCommandsToRemove = _lastCommandIndex - _currentCommandIndex;
_history.RemoveRange(_currentCommandIndex + 1, numCommandsToRemove);
_lastCommandIndex -= numCommandsToRemove;
}
_history.Add(command);
if (NumCommands > _maxSize)
{
_history.RemoveAt(0);
if (_currentCommandIndex == _lastCommandIndex)
_currentCommandIndex--;
_lastCommandIndex--;
}
_currentCommandIndex++;
_lastCommandIndex++;
EventsHelper.Fire(_currentCommandChangedEvent, this, EventArgs.Empty);
}
internal static CommandInfo CreateCommandInfo(UndoableCommand command)
{
if (command is MemorableUndoableCommand)
return new MemorableCommandInfo((MemorableUndoableCommand) command);
else if (command is CompositeUndoableCommand)
return new CompositeCommandInfo((CompositeUndoableCommand) command);
return new CommandInfo(command);
}
