ImageGear provides a metadata dictionary that stores necessary information for all known metadata tags of all supported formats.

The application can obtain an information record for any tag that is present in the dictionary, using ImGearMetadataDictionary.LookUp Method.

All tag information records implement IImGearMetadataDictRecord Interface. This interface provides minimal information for a tag a its name. This is sufficient for most ImageGear supported formats. These formats use ImGearCommonMetadataDictRecord Structure for storing tag information. This structure only contains the tag and its name.

Dictionary records for DICOM tags contain additional fields, such as ValueRepresentation and MaxMultiplicity. ImageGear uses ImGearDICOMMetadataDictRecord Class to store DICOM tag information.

ImageGear contains an expansive set of predefined dictionary records. In addition, the dictionary allows adding new records for new or custom tags that are not present in the predefined dictionary. The dictionary also allows overwriting predefined information for a tag with a custom one. Use ImGearMetadataDictionary.AddRecord Method for this.

Use ImGearMetadataDictionary.Reset Method to reset the dictionary to its initial state. This method removes all records that were added by the AddRecord Method, and leaves only predefined records.

Metadata dictionary only affects General Metadata API. It does not affect Simplified Metadata API.