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maxLength

maxLength specifies maximum length in bytes for strings input to a field.

Inside the following text widgets: TextField, TextArea, FunctionField can be enabled maxlength tracker that shows number of the characters left inside the widget field. To enable the maxlength tracker:

Form XML code:

<element_name maxLength="125">

By default, maxLength is not specified and is absent from the form and theme XML codes. The property value will appear in the form and theme XML codes only once it is specified.

Possible values:

any integer (limited by the data type (and size) of a variable assigned to the field)

Default value:

depends of the data type (and size) of a variable assigned to the field

Associated containers, widgets and theme elements:

Associated 4gl syntax:

INPUT

INPUT ARRAY

Associated ui methods:

SetMaxLength ↓

GetMaxLength ↓

Influence and behavior:

The value set to the property specifies the maximum length (in bytes) you will be able to input into the field:

lycia form designer:

For the first textArea (identifier=f1), maxLength=5:

For the second textArea (identifier=f2), maxLength=10:

4gl code sample:

MAIN
DEFINE f1, f2 STRING
OPEN WINDOW w WITH FORM "maxLength" ATTRIBUTE(BORDER)
MENU
  COMMAND "input"
    INPUT BY NAME f1 WITHOUT DEFAULTS
    INPUT BY NAME f2 WITHOUT DEFAULTS
  COMMAND "exit"
    EXIT MENU
END MENU
END MAIN

intended input:

1234567890

runtime appearance:

When set together with autonext, the property can be used in order to increase the interface user-friendliness.

At runtime, you can use ui methods to find out the maximum length of the data string which can be input to the field and change it:

LET widget_var= ui.<widget>.ForName("widget_id1")

CALL widget_var.setMaxLength(<int>)

4gl code sample:

DEFINE ta_1 ui.TextArea
...
LET ta_1 = ui.TextArea.ForName("f1")
CALL ta_1.setMaxLength(10)

DEFINE ta_2 ui.TextArea
...
LET ta_2 = ui.TextArea.ForName("f2")
CALL ta_2.setMaxLength(5)

initial runtime appearance:

runtime appearance after ui methods were applied:

LET widget_var = ui.<widget>.ForName("widget_id1")

DISPLAY widget_var.getMaxLength()

4gl code sample:

MAIN
DEFINE f1, f2 STRING,
       ta_1, ta_2 ui.TextArea
OPEN WINDOW w WITH FORM "maxLength" ATTRIBUTE(BORDER)
LET ta_1 = ui.TextArea.ForName("f1")
LET ta_2 = ui.TextArea.ForName("f2")
MENU
  COMMAND "display"
    DISPLAY "With f1, maxLength=", ta_1.getMaxLength()
    DISPLAY "With f2, maxLength=", ta_2.getMaxLength()
  COMMAND "change"
    CALL ta_1.setMaxLength(10)
    CALL ta_2.setMaxLength(5)
  COMMAND "exit"
    EXIT MENU
END MENU
END MAIN

runtime appearance: