Public Function GetPreviousElement( _
   ByVal element As DicomElement, _
   ByVal tree As Boolean, _
   ByVal includeVolatile As Boolean _
) As DicomElement

Visual Basic (Usage)	Copy Code
Dim instance As DicomDataSet Dim element As DicomElement Dim tree As Boolean Dim includeVolatile As Boolean Dim value As DicomElement   value = instance.GetPreviousElement(element, tree, includeVolatile)

public DicomElement GetPreviousElement( 
   DicomElement element,
   bool tree,
   bool includeVolatile
)

public: DicomElement* GetPreviousElement( 
   DicomElement* element,
   bool tree,
   bool includeVolatile
) 

public:
DicomElement^ GetPreviousElement( 
   DicomElement^ element,
   bool tree,
   bool includeVolatile
) 

Parameters

element

An item in the Data Set. The item in the Data Set that immediately precedes this item will be returned.

tree

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

includeVolatile

true to retrieve the previous element, volatile or non-volatile; false to retrieve the previous non-volatile element.

Return Value

If the Data Set is evaluated as a list, the previous 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.

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

GetFirstElement

GetLastElement

GetNextElement

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

GetRootElement

GetParentElement

GetChildElement

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

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

Target Platforms: Microsoft .NET Framework 2.0, Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

Reference