Manipulating Bar Code controls programmatically

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Help / Developing an application or website / Controls, windows and pages / Controls: Available types / Bar Code control

Overview
Displaying a bar code in a Bar Code control
Displaying a bar code in a Bar Code control
Retrieving in a Bar Code control the value read by a specific device
Retrieving the value of the bar code displayed in the Bar Code control
Properties specific to Bar Code controls

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The Bar Code control

Manipulating Bar Code controls programmatically

Overview

WINDEV, WEBDEV and WINDEV Mobile allow you to programmatically manipulate Bar Code controls. To do so, use the variable of the Bar Code control in the code.

The variable of the Bar Code control corresponds to the name of the control. This variable is a text variable.

Displaying a bar code in a Bar Code control

To display a bar code in a Bar Code control, simply assign a value.

For example:

direct assignment:
BAC_BarCodeControl = "123456789"
assignment using a variable:
BAC_BarCodeControl = Products.BarCode

QR Codes:
To display a QR code in a Bar Code control, you can use a variable of type BarCode.
Remark: In a window or page, if the field is associated with a data file item, the value entered is automatically retrieved using the ScreenToFile or PageToFile function.. For more details, see Binding Bar Code controls to items.

Retrieving in a Bar Code control the value read by a specific device

You can read the bar codes and display the corresponding value on the screen. To read a bar code:

Connect a specific device to the serial port of your computer.
Read the bar code value using the following serial port functions:
sOpen Opens and initializes:
a serial port.
a parallel port.
an infrared port.
sRead Reads a character string in the entry buffer of the specified serial port.
Initialize the read value in a Bar Code control corresponding to the type of bar code read.

Example used to read a bar code with a specific device connected to the COM1 serial port:

// Declare the variables
// Define the number of characters that must be read
NbCharToRead is int = 13
// Number of pending bytes in the buffer
NbPendingBytes is int
BufferPrn is string // Content of the buffer
SerialPort is int = 1 // Serial port COM1

// Open and initialize the serial port COM1
IF sOpen(SerialPort, 5000, 5000) THEN
// Read the bar code
// Retrieve the number of pending bytes
NbPendingBytes = sInEntryQueue(SerialPort)
// Retrieve the value of the bar code only
// if at least 13 characters have been read
IF NbPendingBytes >= NbCharToRead THEN
BufferPrn = sRead(SerialPort, NbPendingBytes)
// Retrieve the first 13 characters read
BufferPrn = Left(BufferPrn, 13)
// Display the bar code value in the
// "EDT_BarCode" edit control
EDT_BarCode = BufferPrn
END
END

Retrieving the value of the bar code displayed in the Bar Code control

To retrieve the bar code value:

perform a simple assignment.
For example:
BarCodeValue = BAC_BarCodeControl
retrieve part of the value.
For example:
BeginningBarCode = Left(BAC_BarCodeControl, 3)
use the Value property.

Remark: If the field is associated with an item in a data file, the value entered is automatically retrieved using the ScreenToFile function.. For more details, see Binding Bar Code controls to items.

Properties specific to Bar Code controls

The following properties can be used to programmatically manipulate Bar Code controls.


DndSource	Gets and sets the behavior of the source control during a drag-and-drop operation.
DndTarget	Gets and sets the behavior of the target control during a drag-and-drop operation.
HorizontalAlignment	Gets and sets the horizontal alignment of a Bar Code control.
VerticalAlignment	Gets and sets the vertical alignment of a Bar Code control.

For a complete list of the WLanguage properties that can be used with a Bar Code control, see Bar Code control properties.