Attributes are used to control the behavior and appearance of DCL tiles in a dialog definition.
The value of an attribute must be one of the following data types:
Numeric values (both integers and real numbers) that represent distances, such as the width or height of a tile, are expressed in character-width or character-height units.
A fractional real number must have a leading digit: for example, 0.1, not .1.
A quoted string consists of text enclosed in quotation marks (""). Attribute values are case-sensitive: B1 is not the same as b1. If the string must contain a quotation mark, precede the quotation mark character with a backslash (\"). Quoted strings can contain other control characters as well. The characters recognized by DCL are shown in the following table:
|
Control characters allowed in DCL strings |
|
|---|---|
|
Control character |
Meaning |
|
\" |
quote (embedded) |
|
\\ |
backslash |
|
\n |
newline |
|
\t |
horizontal tab |
A reserved word is an identifier made up of alphanumeric characters, beginning with a letter. For example, many attributes require a value of either true or false. Reserved words are also case-sensitive: True does not equal true.
Like reserved words and strings, attribute names are case-sensitive; for example, you cannot assign a width by calling it Width.
Application programs always retrieve attributes as strings. If your application uses numeric values, it must convert them to and from string values.
Some attributes, such as width and height, are common to all tiles. Attribute specifications are optional. Many attributes have default values that are used if the attribute is not specified. Other attributes are specifically meant for certain kinds of tiles—for example, the background color of an image. If you attempt to assign this attribute to a different kind of tile, AutoCAD ® may report an error. Usually, it ignores the attribute.