Name
CDbl Function
Named Arguments
No
Syntax
CDbl(expression
)
-
expression
Use: Required
Data Type: Numeric or String
-1.79769313486232E308 to -4.94065645841247E-324 for negative values, and 4.94065645841247E-324 to 1.79769313486232E308 for positive values
Return Value
expression
cast as a Double data type.
Description
Converts expression
to a Double data type
Rules at a Glance
If the value of
expression
is outside the range of the double data type, an overflow error is generated.expression
must evaluate to a numeric value; otherwise, a type-mismatch error is generated.
Example
Dim dblMyNumber as Double If IsNumeric(sMyNumber) then dblMyNumber = CDbl(sMyNumber) End If
Programming Tips and Gotchas
When converting a string representation of a number to a numeric value, the data type conversion functions, such as
CDbl
, are preferable to the older function,Val
. This is because the data type conversion functions take account of the system’s regional settings, whereasVal
recognizes only the period as a decimal separator. For example, if a user inputs a value of 6,231,532.11,CDbl
correctly converts it to a double with a value of 6231532.11, whileVal
returns a value of 6.Use
IsNumeric
to test whetherexpression
evaluates to a number.Like most conversion functions,
CDbl
is not actually a function in the Microsoft.VisualBasic namespace. Instead, it is similar to a Visual C++ macro; the compiler translates the function call into inline code.
See Also
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