/// <summary>
 ///         constructor.
 /// </summary>
 /// <param name="fileNumber">the block index the file begins at in the parent container file.</param>
 /// <param name="name">the name of this virtual item (file name or directory name).</param>
 /// <param name="parentDirectory">an instance of the parent directory.</param>
 /// <param name="containerFile">an instance of the parent container file.</param>
 internal VirtualItem(uint fileNumber, string name, VirtualDirectory parentDirectory,
     ContainerFile containerFile)
 {
     FileNumber = fileNumber;
                 Name = name;
                 ParentDirectory = parentDirectory;
                 ContainerFile = containerFile;
 }
 /// <summary>
 ///         constructor.
 /// </summary>
 /// <param name="fileNumber">the block index the file begins at in the parent container file.</param>
 /// <param name="name">the name of this virtual item (file name or directory name).</param>
 /// <param name="parentDirectory">an instance of the parent directory.</param>
 /// <param name="containerFile">an instance of the parent container file.</param>
 internal VirtualDirectory(uint fileNumber, string name, VirtualDirectory parentDirectory,
     ContainerFile containerFile)
     : base(fileNumber, name, parentDirectory, containerFile)
 {
 }
 /// <summary>
 ///         constructor.
 /// </summary>
 /// <param name="firstBlockIndex">the block index the file begins at in the parent container file.</param>
 /// <param name="name">the name of this virtual item (file name or directory name).</param>
 /// <param name="parentDirectory">an instance of the parent directory.</param>
 /// <param name="containerFile">an instance of the parent container file.</param>
 internal VirtualFile(uint firstBlockIndex, string name, VirtualDirectory parentDirectory, ContainerFile containerFile)
     : base(firstBlockIndex, name, parentDirectory, containerFile)
 {
 }
 /// <summary>
 ///         constructor.
 /// </summary>
 /// <param name="containerFile">the container file instance the virtual disk is operating on.</param>
 private VirtualDisk(ContainerFile containerFile)
 {
     _containerFile = containerFile;
 }