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GetPreviousKey Method

Summary

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

Syntax
C#
VB
Java
C++
public DicomElement GetPreviousKey( 
   DicomElement element, 
   bool tree 
) 
Public Function GetPreviousKey( _ 
   ByVal element As DicomElement, _ 
   ByVal tree As Boolean _ 
) As DicomElement 
public DicomElement getPreviousKey(DicomElement element, boolean tree) 
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 VB) if there is no item preceding element (element is the first item in the Data Set).

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. getpvtr.gif

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

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

Example

For an example, refer to Reset.

Requirements

Target Platforms

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