DdsBarcodeFieldTagHelper class

Estimated reading time: 7 minutes

Defines a character input element (code) that may be read from a video source, by scanning images on each frame, identifying patterns according to Barcode or QR Code pictorial representation.

Namespace: ASNA.QSys.Expo.Tags Assembly: ASNA.QSys.Expo.Tags.dll

Inheritance: Object –> TagHelper –> FieldBase –> DdsFieldBase –> DdsCharFieldTagHelper

Remarks

The Barcode scanning feature requires at least one video device accesible to the Web Browser. Typically the video device is the main Mobile Phone camera (with auto-focus).

The Browser requires the appropriate permissions to access the Camera.

Modern Mobile Phones may have more than one camera. The DdsBarcodeFieldTag looks for one with a title including one of these words: Back or back. If no camera identifies itself with a title containing one of these words, the first camera listed (with video capabilities) is selected by default.

A video-preview window is presented (below the DdsBarcodeFieldTag instance - pushing momentarily the page down), with a collection of small buttons to the right of the window labeld “1”, “2”, “3”, etc. These buttons represent the first, second, third, etc. cameras. Tapping (or clicking) any of the buttons will activate that camera.

There is a button labeled “x” available to Cancel the scanning process prematurely.

As soon as the code in the Barcode is identified:

  1. An audible alarm sounds to notify that the Barcode has been succesfuly read.
  2. The value (code) read is pasted into the value of the DdsBarcodeFieldTag input instance.
  3. The Video preview (with the available options as buttons) is removed from the Page.

Normally the Application will expect only one or two Barcode formats to be used. The barcode detection performance can be improved if the Barcode format(s) is enabled by setting the appropriate Hint value to true (for any of the listed properties below).

Note: Some browsers restrict the use of the camera for secure connections. Beware that http protocol may NOT work for Barcode scanning. The development use of Self-signed certificate may require additional user consent to display pages on your site.

Important: DdsBarcodeFieldTag requires additional site configuration to work properly. Please read Expo Client-Side Barcode Scanning Support on the Manuals / Configuration section.

Properties

Type Name Description
AidKey AidKey Attention or Function key to be posted when Barcode is detected (as if the user had pressed that keyboard key).
String HintAllowEAN_Extensions Comma separated list of lengths, listing the allowed extension lengths for EAN or UPC Barcodes. For example “2, 5”. If it is optional to have an extension, do not set this hint. If this is set, and a UPC or EAN Barcode is found but an extension is not, then no result will be returned at all.
String HintAllowedITF_Lengths When Barcode format ITF is detected, only the valid lengths of encoded data in this comma separated list of lengths is considered valid. If not set, it is assumed the valid ITF lengths are: 6, 8, 10, 12, 14.
Boolean HintAssumeCode39CheckDigit When Barcode format CODE_39 is detected and this property is true, treat the last data character as a check digit, not data, and verify that the checksum passes.
Boolean HintAssumeGS1_CODE_128 Assume the Barcode is being processed as a GS1 Barcode, and modify behavior as needed. Affects FNC1 handling for CODE 128 (aka GS1-128)
String HintCharacterSet Specifies what character encoding to use where applicable (“SJIS”, “GB2312”, “ISO8859_1”, “EUC_JP” or “UTF8” ). Defaults to “UTF8”
Boolean HintEnableCODE39_ExtendedMode Enable CODE 39 Extended Mode. When enabled, Code 39 reader will attempt to decode extended sequences in the text.
Boolean HintFormatAZTEC Aztec 2D Barcode format likely used to be used to represent the value for this field. (Use “AZTEC” if using HintFormatOrderedList property).
Boolean HintFormatCODABAR CODABAR 1D Barcode format likely used to be used to represent the value for this field. (Use “CODABAR” if using HintFormatOrderedList property).
Boolean HintFormatCODE_128 Code 128 1D Barcode format likely used to be used to represent the value for this field. (Use “CODE_128” if using HintFormatOrderedList property).
Boolean HintFormatCODE_39 Code 39 1D Barcode format likely used to be used to represent the value for this field. (Use “CODE_39” if using HintFormatOrderedList property).
Boolean HintFormatCODE_93 Code 93 1D Barcode format likely used to be used to represent the value for this field. (Use “CODE_93” if using HintFormatOrderedList property).
Boolean HintFormatDATA_MATRIX Data Matrix 2D Barcode format likely used to be used to represent the value for this field. (Use “DATA_MATRIX” if using HintFormatOrderedList property).
Boolean HintFormatEAN_13 EAN-13 1D Barcode format likely used to be used to represent the value for this field. (Use “EAN_13” if using HintFormatOrderedList property).
Boolean HintFormatEAN_8 EAN-8 1D Barcode format likely used to be used to represent the value for this field. (Use “EAN_8” if using HintFormatOrderedList property).
Boolean HintFormatITF ITF 1D Barcode format likely used to be used to represent the value for this field. (Use “ITF” if using HintFormatOrderedList property).
Boolean HintFormatMAXICODE MaxiCode 2D Barcode format likely used to be used to represent the value for this field. (Use “MAXICODE” if using HintFormatOrderedList property).
String HintFormatOrderedList For advanced Hint Format configuration, enter on this property a list of string names indicating the possible formats the Barcode reader may encounter.The order in the list may optimize the scanning performance. List first the most likely format identifiers to be encountered.For the name of the identifiers see the help on each of the boolean HintFormatXXXX properties. Use blanks, commas or semi-colons to separate each format identifier name.
Boolean HintFormatPDF_417 PDF417 Barcode format likely used to be used to represent the value for this field. (Use “PDF_417” if using HintFormatOrderedList property).
Boolean HintFormatQR_CODE QR Code 2D format likely used to be used to represent the value for this field. (Use “QR_CODE” if using HintFormatOrderedList property).
Boolean HintFormatRSS_14 RSS_14 Barcode format likely used to be used to represent the value for this field. (Use “RSS_14” if using HintFormatOrderedList property).
Boolean HintFormatRSS_EXPANDED RSS EXPANDED Barcode format likely used to be used to represent the value for this field. (Use “RSS_EXPANDED” if using HintFormatOrderedList property).
Boolean HintFormatUPC_A UPC-A 1D Barcode format likely used to be used to represent the value for this field. (Use “UPC_A” if using HintFormatOrderedList property).
Boolean HintFormatUPC_E UPC-E 1D Barcode format likely used to be used to represent the value for this field. (Use “UPC_E” if using HintFormatOrderedList property).
Boolean HintFormatUPC_EAN_EXTENSION UPC/EAN Extension Barcode format likely used to be used to represent the value for this field. (Use “UPC_EAN_EXTENSION” if using HintFormatOrderedList property).
Boolean HintPureBarcode Barcodes are “pure” meaning, monochrome images which contains only an unrotated, unskewed, image of a code, with some white border around it.Enabling this hint (when applicable) optimizes detection performance significantly.
Boolean HintTryHarder Spend more time to try to find a Barcode; optimize for accuracy, not speed.
Int64 ScanningTimeoutSeconds Timeout in seconds for the Barcode to be identified. If no detection succeeds within the timeout (since the scan started), the Preview User Interface is removed (canceling the scan). Set to zero to make it indefinite.