WklBarcode

Dim myWklBarcode As WklBarcode
Set myWklBarcode = Me!ControlName.Object

A QR Code, Code 128 or Data Matrix symbol of a text, drawn from encoders of its own (no external library), in forms, in reports and on UserForms.

None

Fill it like WklStatusLabel: by code through Value, or bound - set the control's Control Source (ControlSource of the Access control) to a field or an expression, and Access writes the value of the current record into Value. A bound barcode never writes back and does not mark the record as changed.

Reports. In the detail section of a report a bound barcode draws the code of each record, in print preview and in a PDF from DoCmd.OutputTo. This is the way to a label with a code per record; no code in Detail_Format is needed.

A value the symbology cannot encode - a letter with an accent for Code 128, the euro sign for Data Matrix - is no error for the form or the report: the control shows the reason instead of a symbol and ErrorText returns it, so one bad record does not stop a list of labels.

The modules are drawn as filled rectangles in whole pixels where they fit, centered in the control; on a printer the code is drawn at 300 dpi, so its edges stay sharp. Black on white is the default, and the control has no color scheme: scanners need contrast, not the database design. Give a QR Code or a Data Matrix symbol a square control; a Code 128 symbol fills the height of its control.

The designer (row Custom [...] of the property sheet in design view, Opening the designer) sets kind, error correction, text and quiet zone with a preview of a sample text, and colors and font; it warns when the modules are not clearly darker than the background.

An ActiveX control: inserted into a form in design view (Form Design › Controls › ActiveX Controls); reports are not supported. VBA reaches it through the Object property of the control, where ControlName is the name of the control on the form.

' Bound in design view: Control Source of bcdProduct = ProductNo.
' By code, for example in an unbound form:
Private Sub cmdCode_Click()
    With Me!bcdProduct.Object
        .Symbology = wsyCode128
        .ShowText = True
        .Value = Me!txtProductNo
        If Len(.ErrorText) > 0 Then MsgBox .ErrorText, vbExclamation
    End With
End Sub

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Property Get Value() As Variant
Property Let Value(RHS As Variant)

Gets or sets the text of the code; bound, Access writes the value of the Control Source into it on every record change.

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Property value: Variant – Any value; numbers and dates are encoded as their text in the regional settings of Windows. Null or an empty text shows nothing.

The value is not stored with the form, and the control never reports it back to Access. After a value is set, ErrorText says whether it could be encoded.

Read/write.

None

Declared by WklBarcode.

Property Get Symbology() As WklSymbology
Property Let Symbology(RHS As WklSymbology)

Gets or sets the kind of code.

None

Property value: `WklSymbology` – wsyQrCode (default), wsyCode128 or wsyDataMatrix.

QR Code encodes any text (as UTF-8; digits and capital letters take less room). Code 128 encodes ASCII only (characters 0-127) and switches between its code sets for the shortest symbol. Data Matrix (ECC 200, square) encodes ISO-8859-1, which includes the German umlauts but not the euro sign. Values outside the enumeration raise wkeInvalidValue.

Read/write.

None

Declared by WklBarcode.

Property Get ErrorCorrection() As WklErrorCorrection
Property Let ErrorCorrection(RHS As WklErrorCorrection)

Gets or sets how much of a QR Code may be damaged and still be read.

None

Property value: `WklErrorCorrection` – wecLow, wecMedium (default), wecQuartile or wecHigh.

A higher level makes the code larger for the same text. Only QR Code uses it; Code 128 has a check character, and Data Matrix ECC 200 has a fixed error correction. Values outside the enumeration raise wkeInvalidValue.

Read/write.

None

Declared by WklBarcode.

Property Get ShowText() As Boolean
Property Let ShowText(RHS As Boolean)

Gets or sets whether the text stands readable below the code.

None

Property value: Boolean – True: the text below the code, in FontName and FontSize; False (default).

Read/write.

None

Declared by WklBarcode.

Property Get QuietZone() As Long
Property Let QuietZone(RHS As Long)

Gets or sets the free margin around the code, in modules.

None

Property value: Long – -1 (default) for the margin the standard asks for (QR Code 4, Code 128 10, Data Matrix 1 module); 0 to 100 for another one.

Scanners need the quiet zone; reduce it only where the space around the control is free anyway. Values outside -1 to 100 raise wkeInvalidValue.

Read/write.

None

Declared by WklBarcode.

Property Get ForeColor() As OLE_COLOR
Property Let ForeColor(RHS As OLE_COLOR)

Gets or sets the color of the dark modules and of the text.

None

Property value: OLE_COLOR – An OLE color; default black.

Read/write.

None

Declared by WklBarcode.

Property Get BackColor() As OLE_COLOR
Property Let BackColor(RHS As OLE_COLOR)

Gets or sets the background color.

None

Property value: OLE_COLOR – An OLE color; default white.

Most scanners read only dark modules on a light background; the designer warns about other choices.

Read/write.

None

Declared by WklBarcode.

Property Get FontName() As String
Property Let FontName(RHS As String)

Gets or sets the font of the text below the code.

None

Property value: String – A font name; default "Segoe UI". An empty name raises wkeInvalidValue.

Read/write.

None

Declared by WklBarcode.

Property Get FontSize() As Long
Property Let FontSize(RHS As Long)

Gets or sets the size of the text below the code.

None

Property value: Long – Points, 6 to 72; default 9. Other values raise wkeInvalidValue.

Read/write.

None

Declared by WklBarcode.

Property Get ErrorText() As String

Gets why the current value cannot be shown as a code.

None

Property value: String – The reason, for example which character Code 128 cannot encode; empty when the value is encoded or there is no value.

Read-only.

None

Declared by WklBarcode.

Property Get ModuleCount() As Long

Gets the number of modules in one row of the current code.

None

Property value: Long – The width of the symbol in modules, without the quiet zone (21 for the smallest QR Code); 0 without a code.

Divide the control's width by ModuleCount plus twice the quiet zone to see how many pixels or twips one module gets; scanners need at least about 0.25 mm per module in print.

Read-only.

None

Declared by WklBarcode.

Sub SaveImage(ByVal Path As String, Optional ByVal Text As String = "", Optional ByVal ModuleSize As Long = 4)

Writes the code of a text as a picture file.

The picture uses the control's kind, error correction, quiet zone, colors and text settings; a Code 128 symbol is 60 modules high. SaveImage also works on an object made with CreateObject("WklForms.Barcode"), without a form. Another extension, a module size outside 1-50, no text, or a text the kind cannot encode raise wkeInvalidValue; a file that cannot be written raises wkeSourceError.

None

Declared by WklBarcode.

Event Click()

Occurs when the user clicks the code in form view.

None

In a form module: Private Sub <ControlName>_Click(...). Parameters passed by reference can be changed by the procedure.

None

Declared by WklBarcode.