DeleteElement Method

Summary

Deletes the specified item from the Data Set.

Syntax

Objective-C

C++/CLI

Java

public DicomElement DeleteElement( 
   DicomElement element 
)

- (nullable LTDicomElement *)deleteElement:(LTDicomElement *)element NS_SWIFT_NAME(deleteElement(_:));

public DicomElement deleteElement(DicomElement element)

public: 
DicomElement^ DeleteElement(  
   DicomElement^ element 
)

Parameters

element
The item to be deleted.

Return Value

An adjacent item if there is one. If the item being deleted has a sibling (same level, same parent), following it, the returned object will point to this sibling. If the item being deleted does not have a sibling following it, but has a sibling preceding it, the returned object points to the preceding sibling. If the item being deleted is an only child, the returned object points to the parent. If the item being deleted has no siblings and no parent, the method returns a null reference (Nothing in VB).

Remarks

You can remove all items from the Data Set using the DicomDataSet.Reset method. Since the Data Set is stored internally as a tree, the deletion must be carried out as a tree.

When deleting an item from the tree, if the item being deleted has a sibling (same level, same parent), following it, the object returned by the method points to this sibling. If the item being deleted does not have a sibling following it, but has a sibling preceding it, the returned object points to the preceding sibling. If the item being deleted is an only child, the returned object points to the parent. If there is no parent, the method returns a null reference (Nothing in VB). Below are illustrations of these situations.

For the sake of these illustrations, the order of siblings is top to bottom. A preceding sibling is drawn above the sibling it precedes, a following sibling is drawn below the sibling it follows.

Please note that the numbering of the items of interest is arbitrary, and does not imply order.

In this illustration, item 2 will be deleted. Since it has a following sibling, the returned object will point to item 3.

In this illustration, item 3 will be deleted. Since it does not have a following sibling, but does have a preceding sibling, the returned object will point to item 2.

In this illustration, item 2 will be deleted. Since it is an only child, the returned object will point to the parent, item 1.

In this illustration, item 1 will be deleted. Since it has no siblings and no parent, this method will return a null reference (Nothing in VB).

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:\LEADTOOLS22\Resources\Images"; 
}