/// <summary>
/// Reverts the previous command in the undo buffer, if available.
/// </summary>
/// <returns>True if the undo was executed.</returns>
public bool Undo()
{
if (!this.CanUndo)
{
return(false);
}
var command = this.commands[this.PreviousCommandIndex];
command.Undo();
this.PreviousCommandIndex -= 1;
this.NextCommandIndex -= 1;
var eventArgs = new NefsEditCommandEventArgs(NefsEditCommandEventKind.Undo, command);
this.CommandExecuted?.Invoke(this, eventArgs);
return(true);
}
/// <summary>
/// Executes a command and adds it to the undo buffer.
/// </summary>
/// <param name="command">The command to execute.</param>
public void Execute(INefsEditCommand command)
{
command.Do();
// Clear any redo commands (can only undo after executing a new command)
if (this.NextCommandIndex < this.commands.Count)
{
this.commands.RemoveRange(this.NextCommandIndex, this.commands.Count - this.NextCommandIndex);
}
// Add command
this.commands.Add(command);
// Update command index
this.PreviousCommandIndex = this.NextCommandIndex;
this.NextCommandIndex = this.commands.Count;
// Notifiy command executed
var eventArgs = new NefsEditCommandEventArgs(NefsEditCommandEventKind.New, command);
this.CommandExecuted?.Invoke(this, eventArgs);
}
