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GetPreviousKey Method
See Also 
Leadtools.Dicom Namespace > DicomDataSet Class : GetPreviousKey Method




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.
Returns the item in the Dicom Dir Data Set that immediately precedes the specified item.

Syntax

Visual Basic (Declaration) 
Public Function GetPreviousKey( _
   ByVal element As DicomElement, _
   ByVal tree As Boolean _
) As DicomElement
Visual Basic (Usage)Copy Code
Dim instance As DicomDataSet
Dim element As DicomElement
Dim tree As Boolean
Dim value As DicomElement
 
value = instance.GetPreviousKey(element, tree)
C# 
public DicomElement GetPreviousKey( 
   DicomElement element,
   bool tree
)
Managed Extensions for C++ 
public: DicomElement* GetPreviousKey( 
   DicomElement* element,
   bool tree
) 
C++/CLI 
public:
DicomElement^ GetPreviousKey( 
   DicomElement^ element,
   bool tree
) 

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.

Return Value

The item in the Data Set that immediately precedes the item specified by element, or a null reference (Nothing in Visual Basic) if there is no item preceding element (element is the first item in the Data Set).

Example

For an example, refer to Reset.

Remarks

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

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

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.

If the passed object points to:The method returns an object pointing to:
Item 1null
Item 15Item 14
Item 5Item 4
Item 9Item 8
Item 22Item 21
Item 25Item 24

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

GetFirstKey

GetNextKey

GetLastKey

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

GetRootKey

GetParentKey

GetChildKey

Requirements

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

See Also

Leadtools.Dicom requires a Medical toolkit license and unlock key. For more information, refer to: Raster Pro/Document/Medical Features