VBScript Reference Manual for InduSoft Web Studio

InduSoft Web Studio VBScript Reference Manual
Data Subtype Conversion
VBScript provides several functions that convert a VBScript variable from one data subtype to another.
Since VBScript uses the Variant data type, these functions are not generally required. However, when
passing data between IWS (or CEView) and VBScipt, or calling built-in IWS functions from VBScript
where variables need to be put into the proper argument format, these VBScript data subtype
conversion functions can be very useful.
Data Subtype Conversion Functions
Function Description
CBool() Converts an expression to a variant of subtype Boolean
CByte() Converts an expression to a variant of subtype Byte
CCur() Converts an expression to a variant of subtype Currency
CDate() Converts a valid date and time expression to the variant of subtype Date
CDbl() Converts an expression to a variant of subtype Double
CInt() Converts an expression to a variant of subtype Integer
CLng() Converts an expression to a variant of subtype Long
CSng() Converts an expression to a variant of subtype Single
CStr() Converts an expression to a variant of subtype String
Example:
a = -5.2
b = 4
c = “A”
LState = True
StartDate = #4/6/2005#
StartTime = #10:05:20#
d = CByte(a) ‘ Will generate overflow error, Bytes are only positive
d = CByte(d) ‘ d will equal 5 (Byte)
d = CStr(a + b) ‘ d will be “-1.2” (string)
d = CDate(StartDate + 20) ‘ d will be 4/26/2005 (date)
d = CDate(StartTime) ‘ d will be 10:05:20 am (date/time)
d = CDate(StartTime + 20) ‘ d will be 1/19/1900 10:05:20 am (date/time)
d = CDate(StartTime + #1:5#) ‘ d will be 11:10:20 am
d = CInt(LState) ‘ d will be -1
Since VBScript does not use explicit data typing, one might expect that you would not get a type
mismatch error. This however, is not necessarily true. For example, if you attempted to sum a number
and a string, you will get a type mismatch error. Users are not allowed to freely mix heterogeneous data
even if all data is of type Variant. Again, type Variant allows the variable and constant data type to be
determined at runtime, instead of being explicitly predefined.
More detail on the Data Subtype Conversion Functions is provided in the VBScript Functions section.
Key Notes:
• You can’t pass an alphanumeric string to a conversion function that returns a number
(e.g. CInt() or CLng() functions) if the string has more than one character containing an
ASCII number. If you try to do this, a type mismatch error will occur
• The CStr() function provides the greatest flexibility when converting an expression into
a String data subtype. If you use the CStr() function with a Boolean expression, the
result will be a string of either “True” or “False”. If you use the CStr() function with a
date expression, the date string will follow the operating systems short date format.
• To convert a string into a date data subtype, you can use either the CDate() function, or
simply assign a date value to a variable, enclosing the value in hashes (#) as follows:
MyDate = “#3/22/2006#”
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