GetChildElement Method

Summary

Returns the item in the Data Set that is the first child of the specified item.

Syntax

Objective-C

C++/CLI

Java

public DicomElement GetChildElement( 
   DicomElement element, 
   bool includeVolatile 
)

- (nullable LTDicomElement *)childElement:(LTDicomElement *)element includeVolatile:(BOOL)includeVolatile;

public DicomElement getChildElement(DicomElement element, boolean includeVolatile)

public: 
DicomElement^ GetChildElement(  
   DicomElement^ element, 
   bool includeVolatile 
)

Parameters

element
An item in the Data Set.

includeVolatile
true to retrieve the first child element, volatile or non-volatile; false to retrieve the first non-volatile child element.

Return Value

The item in the Data Set that is the first child of the item specified by element, or a null reference (Nothing in VB) if element has no child items.

Remarks

The child is the offspring one level lower than the specified item. If the specified item has no child items, this method will return a null reference (Nothing in VB). For example:

If the passed object points to:	The method returns an object pointing to:
Item 1	null
Item 2	Item 3
Item 4	Item 5
Item 6	null

The following methods will also help you navigate the Data Set:

A volatile element is an element that can be changed or destroyed in the process of inserting or setting an image. A non-volatile element is an element that must be changed manually; it is not changed or destroyed by inserting or setting an image.

For example, a grayscale image has elements DicomTag.SmallestImagePixelValue, DicomTag.LargestImagePixelValue, etc. If the image is changed to a color image, these elements disappear and the following elements appear: DicomTag.RedPaletteColorLookupTableDescriptor, etc. These are volatile elements since they are changed or destroyed when an image is changed or set.

To retrieve a child element that must be changed manually, i.e., is not volatile, set includeVolatile to false. To retrieve a child element that may be either volatile or non-volatile, set includeVolatile to true.

Example

using Leadtools; 
using Leadtools.Dicom; 
 
 
public void LoadEnumerateSample() 
{ 
   string dicomFileName = Path.Combine(LEAD_VARS.ImagesDir, "DICOM", "image3.dcm"); 
   //Make sure to initialize the DICOM engine, this needs to be done only once  
   //In the whole application 
   DicomEngine.Startup(); 
   using (DicomDataSet ds = new DicomDataSet()) 
   { 
      //Load DICOM File 
      ds.Load(dicomFileName, DicomDataSetLoadFlags.None); 
      //Insert patient name element, if it doesn't already exist 
      DicomElement element = ds.FindFirstElement(null, DicomTag.PatientName, false); 
      if (element == null) 
      { 
         element = ds.InsertElement(null, false, DicomTag.PatientName, DicomVRType.PN, false, 0); 
      } 
      //The dataset should include the patient name element or an error occurred 
      element = ds.FindLastElement(null, DicomTag.PatientName, false); 
      Debug.Assert(element != null); 
      //There can be only one patient element in the root level 
      element = ds.FindPreviousElement(null, false); 
      Debug.Assert(element == null); 
      element = ds.FindNextElement(null, false); 
      Debug.Assert(element == null); 
 
      element = ds.FindFirstElement(null, DicomTag.PatientName, false); 
      //Since the patient name element is in the root level, 
      //GetRootElement will return the same element. 
      DicomElement element1 = ds.GetRootElement(element); 
      Debug.Assert((element1.Tag == element.Tag), "GetRootElement should return same element"); 
 
      //Since the patient name element has no parent then GetParentElement will return null 
      element1 = ds.GetParentElement(element); 
      Debug.Assert(element1 == null, "GetParentElement should return null"); 
 
      //Since the patient name element has no children then GetChildElement will return null 
      element1 = ds.GetChildElement(element, false); 
      Debug.Assert(element1 == null, "GetChildElement should return null"); 
 
      element1 = ds.GetFirstElement(element, false, false); 
      Debug.Assert(element1 != null, "GetFirstElement Can't return null in this case"); 
 
      element1 = ds.GetLastElement(element, false, false); 
      Debug.Assert(element1 != null, "GetLastElement Can't return null in this case"); 
 
      element1 = ds.GetPreviousElement(element, false, true); 
      DicomElement element2 = ds.GetNextElement(element, false, true); 
 
      Debug.Assert(ds.GetElementLevel(element) == 0); 
 
      Debug.Assert(ds.ExistsElement(element)); 
      Debug.Assert(ds.IsVolatileElement(element) == false); 
 
      //Patient Name is not the only element in this level 
      Debug.Assert((element1 != null) && (element2 != null)); 
      //Delete the patient name element 
      ds.DeleteElement(element); 
   } 
   DicomEngine.Shutdown(); 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS23\Resources\Images"; 
}