public IndexerCommand(CommandEntryList parent, Post[] items, int index)
     : base(parent)
 {
     this.items = items;
     this.index = index;
 }
 public RemoveAtCommand(CommandEntryList parent, Post item)
     : base(parent)
 {
     this.item = item;
 }
 public AddCommand(CommandEntryList parent, Post item)
     : base(parent)
 {
     this.items = new Post[] { item };
 }
 public AddCommand(CommandEntryList parent, Post[] items)
     : base(parent)
 {
     this.items = items;
 }
 protected Command(CommandEntryList parent)
 {
     this.parent = parent;
 }