←Select platform

GetFirstKey Method

Summary
Returns the first item in the Dicom Dir Data Set.
Syntax
C#
Objective-C
C++/CLI
Java
public DicomElement GetFirstKey( 
   DicomElement element, 
   bool tree 
) 
- (nullable LTDicomElement *)firstKey:(nullable LTDicomElement *)element tree:(BOOL)tree; 
public DicomElement getFirstKey(DicomElement element, boolean tree) 
public: 
DicomElement^ GetFirstKey(  
   DicomElement^ element, 
   bool tree 
)  

Parameters

element
An item in the Data Set.

tree
true to evaluate the Data Set as a tree; false to evaluate the Data Set as a list.

Return Value

The first item in the Data Set, or a null reference (Nothing in VB) if the Data Set is empty.

Remarks

If the Data Set is evaluated as a tree structure, this method returns the first item on the same level as element with the same parent as element. Please note that the numbering of the items in this first illustration is arbitrary and does not imply order.

getfsttr.gif
If the passed object points to: The method returns an object pointing to:
Item 1 Item 2
Item 3 Item 4
Item 5 Item 5
Item 6 Item 7
null Item 2

If the Data Set is evaluated as a list, the first item in the list is returned. Please note that the numbering of the items in the following illustration does indicate the order of the items when the Data Set is evaluated as a list.

getftlst.gif
If the passed object points to: The method returns an object pointing to:
null Item 1
Item 12 Item 1
Item 14 Item 1
Item 22 Item 1
Item 25 Item 1

The following methods will also help you navigate the Data Set as either a tree or a list:

GetLastKey

GetNextKey

GetPreviousKey

If you evaluate the Data Set as a tree, you can also use the following methods to navigate the tree:

GetRootKey

GetParentKey

GetChildKey

Example
C#
using Leadtools; 
using Leadtools.Dicom; 
 
 
public void DicomDIRSample() 
{ 
   //Make sure to initialize the DICOM engine, this needs to be done only once  
   DicomEngine.Startup(); 
   using (DicomDataSet dicomDIR = new DicomDataSet()) 
   { 
      dicomDIR.Reset(); 
      //Initialize the dataset as a DICOMDIR class 
      dicomDIR.Initialize(DicomClassType.BasicDirectory, DicomDataSetInitializeType.ExplicitVRLittleEndian); 
      Debug.Assert(dicomDIR.InformationClass == DicomClassType.BasicDirectory); 
      Debug.Assert(dicomDIR.InformationFlags == (DicomDataSetFlags.ExplicitVR | DicomDataSetFlags.LittleEndian | DicomDataSetFlags.MetaHeaderPresent)); 
      //Insert a patient level key 
      DicomElement patientKey = dicomDIR.InsertKey(null, DicomDirKeyType.Patient, true); 
      //Insert a study key under the patient key 
      DicomElement studyKey = dicomDIR.InsertKey(patientKey, DicomDirKeyType.Study, true); 
      //Now insert three series keys under the study key 
      DicomElement seriesKey = dicomDIR.InsertKey(studyKey, DicomDirKeyType.Series, true); 
      seriesKey = dicomDIR.InsertKey(studyKey, DicomDirKeyType.Series, true); 
      seriesKey = dicomDIR.InsertKey(studyKey, DicomDirKeyType.Series, true); 
      DicomElement key = dicomDIR.GetRootKey(seriesKey); 
      //Get the key value, You can also call GetKeyValuePtr 
      DicomDirKeyType keyValue = dicomDIR.GetKeyValue(key); 
      //The root key for the series key should be patient 
      Debug.Assert(keyValue == DicomDirKeyType.Patient, "The root key for the series key should be patient in this case"); 
      //Get the parent key for the series, it should be study 
      key = dicomDIR.GetParentKey(seriesKey); 
      keyValue = dicomDIR.GetKeyValue(key); 
      Debug.Assert(keyValue == DicomDirKeyType.Study, "The parent key for the series key should be study in this case"); 
      //The child for the study key should be series 
      key = dicomDIR.GetChildKey(studyKey); 
      keyValue = dicomDIR.GetKeyValue(key); 
      Debug.Assert(keyValue == DicomDirKeyType.Series, "The child for the study key should be series"); 
      //The first key should be patient, if we traverse the DICOMDIR as a list 
      key = dicomDIR.GetFirstKey(studyKey, false); 
      keyValue = dicomDIR.GetKeyValue(key); 
      Debug.Assert(keyValue == DicomDirKeyType.Patient); 
      //The last key should be series, if we traverse the DICOMDIR as a list 
      key = dicomDIR.GetLastKey(studyKey, false); 
      keyValue = dicomDIR.GetKeyValue(key); 
      Debug.Assert(keyValue == DicomDirKeyType.Series); 
      //The key before the study key should be patient, if we traverse the DICOMDIR as a list 
      key = dicomDIR.GetPreviousKey(studyKey, false); 
      keyValue = dicomDIR.GetKeyValue(key); 
      Debug.Assert(keyValue == DicomDirKeyType.Patient); 
      //The key after the study key should be series, if we traverse the DICOMDIR as a list 
      key = dicomDIR.GetNextKey(studyKey, false); 
      keyValue = dicomDIR.GetKeyValue(key); 
      Debug.Assert(keyValue == DicomDirKeyType.Series); 
      //If we delete the study key, the series keys under it will get deleted too 
      dicomDIR.DeleteKey(studyKey); 
      key = dicomDIR.FindFirstKey(null, DicomDirKeyType.Series, false); 
      Debug.Assert(key == null); 
      key = dicomDIR.FindLastKey(null, DicomDirKeyType.Series, false); 
      Debug.Assert(key == null); 
      key = dicomDIR.FindPreviousKey(null, false); 
      Debug.Assert(key == null); 
      key = dicomDIR.FindNextKey(null, false); 
      Debug.Assert(key == null); 
   } 
   DicomEngine.Shutdown(); 
} 
Requirements

Target Platforms

Help Version 23.0.2024.2.29
Products | Support | Contact Us | Intellectual Property Notices
© 1991-2024 LEAD Technologies, Inc. All Rights Reserved.

Leadtools.Dicom Assembly