Converts a value of any data type to a Double value.

This function is similar to CDbl in Visual Basic.

The result of the conversion depends on the data type of <value>, as follows:

Boolean: The return value is 1.0 (True) or 0.0 (False).

Categorical: An error occurs.

Double: <value> is returned unchanged.

Date: The return value is the floating-point number used internally to represent the date.

Long: The return value is equal to <value>, with a fractional part of zero.

NULL values: If <value> is NULL, the return value is 0.0.

Object: If the object has a default property, the value of that property is converted. Otherwise an error occurs.

Text: The string is parsed according to the locale to extract the value. An error occurs if the string does not contain a properly formatted double.