Working with Tags

The tag of a data element consists of an ordered pair of 16-bit values that represent a Group number and an Element number. The tag indicates the type of information stored in the value field of the data element. There are a number of tags that are standard for the DICOM file format. In addition to the standard tags, user-defined tags may also be added.

LEADTOOLS maintains a table (or list) internally of all available tags, standard and user defined. In this documentation the table of available Data Element Tags will be referred to as the Data Element Tag Table. Also provided in this documentation is a table of the default values for the standard tags. To see these default values, refer to the Default Data Element Tag Table.

LEADTOOLS provides a number of methods for maneuvering through and modifying the Data Element Tag Table. All methods pertaining to the Data Element Tag Table have the form xxxTag method or xxxTagxxx method..

For maneuvering through the Data Element Tag Table, LEADTOOLS provides the following methods:

MoveFirstTag method

MoveLastTag method

MovePrevTag method

MoveNextTag method

GetTagCount method

To find specific items, based on either the tag or an index into the table, use the FindTag method and the FindIndexTag method.

To insert new items in the Data Element Tag Table, use the InsertTag method.

You can delete individual items from the table using the DeleteTag method, or you can delete all items from the table, using the ResetTag method.

To change the name of an item already in the table, use the SetTagName method.

Finally, to reset the Data Element Tag Table to the default values, use the DefaultTag method.

Whenever you access an item within the Data Element Tag Table, the CurrentTag property is updated with the selected item.

For more information on tags, refer to An Overview of the DICOM File Format or the DICOM Standard.