private void AddTagNodes(TreeNode parent, DicomSequenceItem record)
		{
			foreach (DicomAttribute attrib in record)
			{
				string name;
				if (attrib is DicomAttributeSQ || attrib is DicomAttributeOB || attrib is DicomAttributeOW || attrib is DicomAttributeOF)
					name = attrib.ToString();
				else
				{
					name = String.Format("{0}: {1}", attrib.Tag.ToString(), attrib.ToString());
				}
				TreeNode tagNode = new TreeNode(name);
				parent.Nodes.Add(tagNode);

				DicomAttributeSQ sqAttrib = attrib as DicomAttributeSQ;
				if (sqAttrib != null)
				{
					for (int i=0; i< sqAttrib.Count; i++)
					{
						TreeNode sqNode = new TreeNode("Sequence Item");
						tagNode.Nodes.Add(sqNode);
						AddTagNodes(sqNode, sqAttrib[i]);
					}
				}
			}
		}

		/// <summary>
		/// Creates the PurposeOfReferenceCodeSequence in the underlying collection. Type 3.
		/// </summary>
		public CodeSequenceMacro CreatePurposeOfReferenceCodeSequence()
		{
			var dicomAttribute = DicomAttributeProvider[DicomTags.PurposeOfReferenceCodeSequence];
			if (dicomAttribute.IsNull || dicomAttribute.IsEmpty)
			{
				var dicomSequenceItem = new DicomSequenceItem();
				dicomAttribute.Values = new[] {dicomSequenceItem};
				var sequenceType = new CodeSequenceMacro(dicomSequenceItem);
				return sequenceType;
			}
			return new CodeSequenceMacro(((DicomSequenceItem[]) dicomAttribute.Values)[0]);
		}

		/// <summary>
		/// Creates the MaskSubtractionSequence in the underlying collection. Type 3.
		/// </summary>
		public IMaskSubtractionSequence CreateMaskSubtractionSequence()
		{
			DicomAttribute dicomAttribute = base.DicomAttributeProvider[DicomTags.MaskSubtractionSequence];
			if (dicomAttribute.IsNull || dicomAttribute.Count == 0)
			{
				DicomSequenceItem dicomSequenceItem = new DicomSequenceItem();
				dicomAttribute.Values = new DicomSequenceItem[] {dicomSequenceItem};
				IMaskSubtractionSequence sequenceType = new MaskSubtractionSequenceItem(dicomSequenceItem);
				sequenceType.InitializeAttributes();
				return sequenceType;
			}
			return new MaskSubtractionSequenceItem(((DicomSequenceItem[]) dicomAttribute.Values)[0]);
		}

		/// <summary>
		/// Creates the MaskSubtractionSequence in the underlying collection. Type 1C.
		/// </summary>
		public MaskSubtractionSequenceIod CreateMaskSubtractionSequence()
		{
			var dicomAttribute = DicomAttributeProvider[DicomTags.MaskSubtractionSequence];
			if (dicomAttribute.IsNull || dicomAttribute.IsEmpty)
			{
				var dicomSequenceItem = new DicomSequenceItem();
				dicomAttribute.Values = new[] {dicomSequenceItem};
				var sequenceType = new MaskSubtractionSequenceIod(dicomSequenceItem);
				sequenceType.InitializeAttributes();
				return sequenceType;
			}
			return new MaskSubtractionSequenceIod(((DicomSequenceItem[]) dicomAttribute.Values)[0]);
		}

		/// <summary>
		/// Creates the value of ReferencedSopSequence in the underlying collection. Type 1.
		/// </summary>
		public ISopInstanceReferenceMacro CreateReferencedSopSequence()
		{
			DicomAttribute dicomAttribute = base.DicomAttributeProvider[DicomTags.ReferencedSopSequence];
			if (dicomAttribute.IsNull || dicomAttribute.Count == 0)
			{
				DicomSequenceItem dicomSequenceItem = new DicomSequenceItem();
				dicomAttribute.Values = new DicomSequenceItem[] {dicomSequenceItem};
				SopInstanceReferenceMacro iodBase = new SopInstanceReferenceMacro(dicomSequenceItem);
				iodBase.InitializeAttributes();
				return iodBase;
			}
			return new SopInstanceReferenceMacro(((DicomSequenceItem[]) dicomAttribute.Values)[0]);
		}

		public void TestSequenceImplicitVr2()
		{
			var syntax = TransferSyntax.ImplicitVrLittleEndian;
			var sq = new DicomAttributeSQ(DicomTags.IconImageSequence);

			var item1 = new DicomSequenceItem();
			item1[DicomTags.AccessionNumber].SetStringValue("ABCDEFG");
			sq.AddSequenceItem(item1);

			var item2 = new DicomSequenceItem();
			item2[DicomTags.AccessionNumber].SetStringValue("XYZ");
			sq.AddSequenceItem(item2);

			// note: both sequence and item delimiter tags are calculated as part of the sequence - the item considers only the total length of its contents

			// item1_length = contents(16)
			Assert.AreEqual(16, item1[DicomTags.AccessionNumber].CalculateWriteLength(syntax, DicomWriteOptions.None), "Attr1 Length");
			Assert.AreEqual(16, item1.CalculateWriteLength(syntax, DicomWriteOptions.None), "Item1 Length");

			// item2_length = contents(12)
			Assert.AreEqual(12, item2[DicomTags.AccessionNumber].CalculateWriteLength(syntax, DicomWriteOptions.None), "Attr2 Length");
			Assert.AreEqual(12, item2.CalculateWriteLength(syntax, DicomWriteOptions.None), "Item2 Length");

			// sq_length = tag(4) + len(4) + item_tag(4) + item_len(4) + item1_length(16) + item_delimiter_tag(4) + item_delimiter_len(4)
			//                             + item_tag(4) + item_len(4) + item2_length(12) + item_delimiter_tag(4) + item_delimiter_len(4)
			//                             + sq_delimiter_tag(4) + sq_delimiter_len(4)
			var options = DicomWriteOptions.None;
			Assert.AreEqual(76, sq.CalculateWriteLength(syntax, options), "SQ Length (Options={0})", options);

			// sq_length = tag(4) + len(4) + item_tag(4) + item_len(4) + item1_length(16) + item_delimiter_tag(4) + item_delimiter_len(4)
			//                             + item_tag(4) + item_len(4) + item2_length(12) + item_delimiter_tag(4) + item_delimiter_len(4)
			options = DicomWriteOptions.ExplicitLengthSequence;
			Assert.AreEqual(68, sq.CalculateWriteLength(syntax, options), "SQ Length (Options={0})", options);

			// sq_length = tag(4) + len(4) + item_tag(4) + item_len(4) + item1_length(16)
			//                             + item_tag(4) + item_len(4) + item2_length(12)
			//                             + sq_delimiter_tag(4) + sq_delimiter_len(4)
			options = DicomWriteOptions.ExplicitLengthSequenceItem;
			Assert.AreEqual(60, sq.CalculateWriteLength(syntax, options), "SQ Length (Options={0})", options);

			// sq_length = tag(4) + len(4) + item_tag(4) + item_len(4) + item1_length(16)
			//                             + item_tag(4) + item_len(4) + item2_length(12)
			options = DicomWriteOptions.ExplicitLengthSequence | DicomWriteOptions.ExplicitLengthSequenceItem;
			Assert.AreEqual(52, sq.CalculateWriteLength(syntax, options), "SQ Length (Options={0})", options);
		}

		/// <summary>
		/// Initializes a new instance of the <see cref="GraphicAnnotationSequenceItem"/> class.
		/// </summary>
		/// <param name="dicomSequenceItem">The dicom sequence item.</param>
		public GraphicAnnotationSequenceItem(DicomSequenceItem dicomSequenceItem) : base(dicomSequenceItem) {}

		/// <summary>
		/// Creates the PetFrameTypeSequence in the underlying collection. Type 1.
		/// </summary>
		public PetFrameTypeSequenceItem CreatePetFrameTypeSequence()
		{
			var dicomAttribute = DicomAttributeProvider[DicomTags.PetFrameTypeSequence];
			if (dicomAttribute.IsNull || dicomAttribute.IsEmpty)
			{
				var dicomSequenceItem = new DicomSequenceItem();
				dicomAttribute.Values = new[] {dicomSequenceItem};
				var sequenceType = new PetFrameTypeSequenceItem(dicomSequenceItem);
				return sequenceType;
			}
			return new PetFrameTypeSequenceItem(((DicomSequenceItem[]) dicomAttribute.Values)[0]);
		}

		/// <summary>
		/// Initializes a new instance of the <see cref="PetFrameTypeSequenceItem"/> class.
		/// </summary>
		/// <param name="dicomSequenceItem">The DICOM sequence item.</param>
		public PetFrameTypeSequenceItem(DicomSequenceItem dicomSequenceItem)
			: base(dicomSequenceItem) {}

			/// <summary>
			/// Initializes a new instance of the <see cref="ReferencedSopSequence"/> class.
			/// </summary>
			/// <param name="dicomSequenceItem">The dicom sequence item.</param>
			public ReferencedSopSequenceType(DicomSequenceItem dicomSequenceItem) : base(dicomSequenceItem) {}

		/// <summary>
		/// Initializes a new instance of the <see cref="XRayCalibrationDeviceUsageFunctionalGroup"/> class.
		/// </summary>
		/// <param name="dicomSequenceItem">The DICOM sequence item.</param>
		public XRayCalibrationDeviceUsageFunctionalGroup(DicomSequenceItem dicomSequenceItem)
			: base(dicomSequenceItem) {}

		private static void MakeVoiLutSequenceB(DicomAttributeCollection dataSet)
		{
			DicomAttribute sequence = dataSet[DicomTags.VoiLutSequence];
			DicomSequenceItem[] items = (DicomSequenceItem[])sequence.Values;
			DicomSequenceItem[] newItems = new DicomSequenceItem[items.Length - 1];
			newItems[0] = items[0];
			newItems[1] = items[2];
			sequence.Values = newItems;
		}

		/// <summary>
		/// Initializes a new instance of the <see cref="ReferencedSopInstanceMacSequence"/> class.
		/// </summary>
		/// <param name="dicomSequenceItem">The dicom sequence item.</param>
		public ReferencedSopInstanceMacSequence(DicomSequenceItem dicomSequenceItem) : base(dicomSequenceItem) {}

		/// <summary>
		/// Initializes a new instance of the <see cref="MrDiffusionFunctionalGroup"/> class.
		/// </summary>
		/// <param name="dicomSequenceItem">The DICOM sequence item.</param>
		public MrDiffusionFunctionalGroup(DicomSequenceItem dicomSequenceItem)
			: base(dicomSequenceItem) {}

		/// <summary>
		/// Initializes a new instance of the <see cref="MrDiffusionSequenceItem"/> class.
		/// </summary>
		/// <param name="dicomSequenceItem">The DICOM sequence item.</param>
		public MrDiffusionSequenceItem(DicomSequenceItem dicomSequenceItem)
			: base(dicomSequenceItem) {}

		/// <summary>
		/// Creates the value of ContentTemplateSequence in the underlying collection. Type 1C.
		/// </summary>
		ContentTemplateSequence IContainerMacro.CreateContentTemplateSequence() {
			DicomAttribute dicomAttribute = base.DicomAttributeProvider[DicomTags.ContentTemplateSequence];
			if (dicomAttribute.IsNull || dicomAttribute.Count == 0) {
				DicomSequenceItem dicomSequenceItem = new DicomSequenceItem();
				dicomAttribute.Values = new DicomSequenceItem[] { dicomSequenceItem };
				ContentTemplateSequence iodBase = new ContentTemplateSequence(dicomSequenceItem);
				iodBase.InitializeAttributes();
				return iodBase;
			}
			return new ContentTemplateSequence(((DicomSequenceItem[])dicomAttribute.Values)[0]);
		}

		private List<DicomFile> SetupImagesWithVoiLutSequenceA(int number)
		{
			List<DicomFile> images = SetupImages(number);

			for (int i = 0; i < images.Count; ++i)
			{
				DicomSequenceItem item = new DicomSequenceItem();
				images[i].DataSet[DicomTags.VoiLutSequence].AddSequenceItem(item);

				item[DicomTags.LutDescriptor].SetStringValue(@"16384\0\16");
				item[DicomTags.LutExplanation].SetStringValue("NORMAL");
				item[DicomTags.LutData].Values = GetLutData(1);

				item = new DicomSequenceItem();
				images[i].DataSet[DicomTags.VoiLutSequence].AddSequenceItem(item);

				item[DicomTags.LutDescriptor].SetStringValue(@"16384\0\16");
				item[DicomTags.LutExplanation].SetStringValue("HARDER");
				item[DicomTags.LutData].Values = GetLutData(2);

				item = new DicomSequenceItem();
				images[i].DataSet[DicomTags.VoiLutSequence].AddSequenceItem(item);

				item[DicomTags.LutDescriptor].SetStringValue(@"16384\0\16");
				item[DicomTags.LutExplanation].SetStringValue("SOFTER");
				item[DicomTags.LutData].Values = GetLutData(3);
			}

			return images;
		}

			/// <summary>
			/// Initializes a new instance of the <see cref="SoftcopyVoiLutSequenceItem"/> class.
			/// </summary>
			/// <param name="dicomSequenceItem">The dicom sequence item.</param>
			public SoftcopyVoiLutSequenceItem(DicomSequenceItem dicomSequenceItem) : base(dicomSequenceItem) { }

		/// <summary>
		/// Initializes a new instance of the <see cref="CalibrationSequenceItem"/> class.
		/// </summary>
		/// <param name="dicomSequenceItem">The DICOM sequence item.</param>
		public CalibrationSequenceItem(DicomSequenceItem dicomSequenceItem)
			: base(dicomSequenceItem) {}

		/// <summary>
		/// Initializes a new instance of the <see cref="PlaneOrientationVolumeSequenceItem"/> class.
		/// </summary>
		/// <param name="dicomSequenceItem">The DICOM sequence item.</param>
		public PlaneOrientationVolumeSequenceItem(DicomSequenceItem dicomSequenceItem)
			: base(dicomSequenceItem) {}