LDicomDS::FindPrevElement

#include "Ltdic.h"

pDICOMELEMENT LDicomDS::FindPrevElement(pElement, bTree)

pDICOMELEMENT pElement;

/* pointer to a DICOMELEMENT structure */

L_BOOL bTree;

/* flag that indicates how to evaluate the Data Set */

Returns a pointer to the previous item in the Data Set with a specific tag.

Parameter

Description

pElement

Pointer to a DICOMELEMENT structure within the Data Set.

bTree

Flag that indicates how the Data Set will be evaluated. Possible values are:

 

Value

Meaning

 

TRUE

Evaluate the Data Set as a tree.

 

FALSE

Evaluate the Data Set as a list.

Returns

!NULL

A pointer to a DICOMELEMENT structure that contains the previous item in the Data Set with a specified tag.

NULL

A previous item with the specified tag was not found.

Comments

Note: This function does not specify a tag to use when searching. However the tag that was used in the last call to LDicomDS::FindFirstElement or LDicomDS::FindLastElement is used by default when searching.

If the Data Set is evaluated as a tree structure, this function returns the previous item on the same level as pElement, with the same parent as pElement, that has tag nTag.

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

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

image\FndFtTr.gif

 

If the passed pointer points to :

The function returns a pointer to :

Item 1

The previous sibling (same level, same parent) of Item 1 that has tag nTag, if such an item exists. If such an item does not exist, the function returns NULL.

Item 2

The previous sibling (same level, same parent) of Item 2 that has tag nTag, if such an item exists. If such an item does not exist, the function returns NULL.

Item 3

The previous sibling (same level, same parent) of Item 3 that has tag nTag, if such an item exists. If such an item does not exist, the function returns NULL.

If the Data Set is evaluated as a list, this function returns the previous item in the entire list that has tag nTag.

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

Please note that the numbering of the items in this illustration does indicate the order of the items when the Data Set is evaluated as a list.

image\FndFtLst.gif

 

If the passed pointer points to :

The function returns a pointer to :

Item 1

The previous item in the list that has tag nTag, if such an item exists. If an item with tag nTag is not found, NULL is returned.

Item 14

The previous item in the list that has tag nTag, if such an item exists. If an item with tag nTag is not found, NULL is returned.

Item 22

The previous item in the list that has tag nTag, if such an item exists. If an item with tag nTag is not found, NULL is returned.

 

The following functions will also help you find elements in the Data Set with a specific tag:

LDicomDS::FindFirstElement

LDicomDS::FindLastElement

LDicomDS::FindNextElement

The following functions will help you find specific modules in the Data Set:

LDicomDS::FindModule

LDicomDS::FindIndexModule

Required DLLs and Libraries

LTDIC

For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application

See Also

Functions:

LDicomDS::FindFirstElement, LDicomDS::FindLastElement, LDicomDS::FindNextElement, LDicomDS::FindModule, LDicomDS::FindIndexModule

Topics:

Working with Data Sets

 

How to Disable the Automatic Loading of the default DICOM IOD Table

Example

For an example, refer to LDicomDS::FindLastElement.