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




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.
Returns the previous item in the Dicom Dir Data Set with a specific key element type.

Syntax

Visual Basic (Declaration) 
Public Function FindPreviousKey( _
   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.FindPreviousKey(element, tree)
C# 
public DicomElement FindPreviousKey( 
   DicomElement element,
   bool tree
)
Managed Extensions for C++ 
public: DicomElement* FindPreviousKey( 
   DicomElement* element,
   bool tree
) 
C++/CLI 
public:
DicomElement^ FindPreviousKey( 
   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 previous item in the Data Set with a specified key element type, or a null reference (Nothing in Visual Basic) if a previous item with the specified key element type was not found.

Example

For an example, refer to Reset.

Remarks

Note: This method does not specify a key element type to use when searching. However the key element type that was used in the last call to FindFirstKey or FindLastKey is used by default when searching.

For the sake of the following illustrations, the order of siblings is top to bottom.

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, that has key element type key.

Please note that the numbering of the items of interest in this first illustration is arbitrary and does not imply order.

If the passed object points to:The method returns an object pointing to:
Item 1The previous sibling (same level, same parent) of Item 1 that has key element type key, if such an item exists. If such an item does not exist, the method returns null.
Item 2The previous sibling (same level, same parent) of Item 2 that has key element type key, if such an item exists. If such an item does not exist, the method returns null.
Item 3The previous sibling (same level, same parent) of Item 3 that has key element type key, if such an item exists. If such an item does not exist, the method returns null.

If the Data Set is evaluated as a list, this method returns the previous item in the entire list that has key element type key.

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 1The previous item in the list that has key element type key, if such an item exists. If an item with key element type key is not found, null is returned.
Item 14The previous item in the list that has key element type key, if such an item exists. If an item with key element type key is not found, null is returned.
Item 22The previous item in the list that has key element type key, if such an item exists. If an item with key element type key is not found, null is returned.

The following methods will also help you find elements in the Data Set with a specific key element type:

FindFirstKey

FindLastKey

FindNextKey

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