Printing bar codes in 4D forms

Use bar code functions in all types of forms; Details Forms, List Forms, Details Forms for Printing, List Forms for Printing, etc. Because bar codes are not usually displayed, but are typically printed, you would likely use bar code functions in; Details Forms for Printing or List Forms for Printing.

Functions in the new bar code plug-in can be used in 4D, just like standard functions in 4th Dimension. There is a specific function to calculate each type of bar code, and a specific font (or a set of fonts) to print each type of bar code. In 4D, wherever you can select or enter command functions, you will now be able to view and select the command functions below the Barcode_CIAXCOM theme;

Design your form

To add bar codes to a form do the following.

- Select the Structure window. If it is not open, select the List of tables window and choose menu Use | Design

- If you want to add bar codes to an existing form, choose menu Design | Edit Form..., or to add bar codes to a new form choose menu Design | New Form...

Tricks with new forms

The first step of the New Form Wizard is to add fields that you want on your form. After you have added the fields you need, you could add additional fields (fields that you do not actually need on the form) and after the form has been created you will be able to modify these additional fields to print bar codes. If all fields in the table are already selected, you can add fields from unrelated tables by selecting All Tables instead of Master Table.

Convert an existing form field to a bar code

With your form open.

To change a field, from printing text, to printing a bar code - do the following;

- Select the field, right-click it and choose pop-up menu Object Properties... to display the Object Properties dialog, or the Property List dialog.

The object method can be as simple as;

or, if you already have some code to trap other events, add this line to the On Display Details event and On Printing Details;

Adding a new form field to a form

A fast way of adding form fields to a form is to copy and paste existing form fields; which has the advantage of keeping the same style.

You can add fields using the Tools Palette (Ctrl-T).

- To display the Tools Palette right-click the form background and from the pop-up menu select Display | Tools Palette.

Select the variable field tool;

Click and drag on the form where you require the bar code. You can always change the size and position later.

Selecting the Variable field type

Select the variable field object that will print the bar code, then choose menu Form | Properties List or Object Properties.

In the Property List box, change the Variable Type property to Variable. 

In the Object Properties box, select the Variable tab and change the Type property to Variable.

Displaying the Object Method dialog

To go directly to the Object Method dialog box, select the form field object that will print the bar code, then choose menu Object | Object Method... (alternatively, right-click the field and choose pop-up menu Object Method...).

If you prefer to use the Property List or Object Properties dialog boxes, then choose menu Form | Display | Properties List or Object Properties.

To go to the Object Method from the Property List box, click the Edit button beside the Object Method property.

To go to the Object Method from the Object Properties box, select the Events tab and click the Object Method button.

Entering the Object Method

To make our variable field object display the contents of a field, this Object Method assigns the field to Variable1, like so;

Now our variable field object displays field [Table 1]AnInteger (i.e. a field called AnInteger in a table called Table 1).

To enter a field name quickly, you can double-click the field name in the Related Fields list (or Master Table list, or All Tables list).

If you wanted to display a field, so that it is formatted with leading zeros, you can use the String function. The Object Method would then be;

The String function a standard 4D function, listed under the String theme.

Selecting a bar code function

You can quickly enter the name of a bar code function by double-clicking it from the list below the Barcode_CIAXCOM theme. Theme Barcode_CIAXCOM is listed under the Commands by Themes list (or Commands by Alphabetical Order list).

The command themes of each plug-in is listed after all of the standard 4D command themes, so the Barcode_CIAXCOM theme is listed at the end, with other plug-in command themes.

This formula produces a Code 128 bar code of field AnInteger in table Table 1, by using function CIAXCOM_CODE128 with an argument of [Table 1]AnInteger

or better still, if we want all of the bar codes to contain zero padded values;

When using complex formulas, test the result of each element of the formula. For example, before using the above formula, test the result of the String function is what you expected;

Some bar code functions (i.e. CIAXCOM_UPCA, CIAXCOM_EAN13, etc.) require a fixed number of numeric digits in the data string argument. This is because some bar code standards only supports a fixed number of digits. So, if you are creating this type of bar code, it is wise to check that all of the values you produce are all of the correct length.

Selecting the correct bar code font

There are several ways of selecting a font, but the best method is to select the form field that you want to print as a bar code, and then;

- Choose menu Font and select the font name

Then to set the font size;

- Choose menu Style | Other... and enter the exact point size