VBScript Conversion Functions
last modified April 4, 2025
VBScript provides several built-in functions to convert between different data types. These functions are essential when you need to ensure data is in the correct format. Conversion functions help prevent errors and ensure consistent behavior in your scripts. This tutorial covers all major VBScript conversion functions with practical examples.
VBScript Conversion Functions Overview
VBScript conversion functions transform data from one type to another. Common
functions include CInt, CLng, CSng,
CDbl, CBool, CStr, CDate,
and CByte. Each function handles specific type conversions.
These functions are particularly useful when working with user input or data from external sources. They help ensure values are in the expected format before processing. Understanding these functions is crucial for robust script development.
Converting to Integer with CInt
The CInt function converts an expression to an Integer subtype. It
rounds fractional values to the nearest integer. If the value is outside the
Integer range (-32,768 to 32,767), an error occurs. This is useful for whole
number calculations.
Dim num1, num2, num3
num1 = CInt("123") ' String to Integer
num2 = CInt(45.67) ' Double to Integer (rounds to 46)
num3 = CInt(True) ' Boolean to Integer (True = -1)
WScript.Echo "num1: " & num1
WScript.Echo "num2: " & num2
WScript.Echo "num3: " & num3
This example shows different conversions to Integer. Notice how the Boolean value True converts to -1. The function handles string representations of numbers and performs rounding for floating-point values.
Converting to String with CStr
The CStr function converts any expression to a String subtype. This
is useful for displaying values or concatenating with other strings. It handles
all VBScript data types including numbers, dates, and Booleans.
Dim str1, str2, str3, str4 str1 = CStr(123) ' Integer to String str2 = CStr(45.67) ' Double to String str3 = CStr(#4/15/2025#) ' Date to String str4 = CStr(False) ' Boolean to String WScript.Echo "str1: " & str1 WScript.Echo "str2: " & str2 WScript.Echo "str3: " & str3 WScript.Echo "str4: " & str4
This example demonstrates converting various data types to strings. The output shows how different values are represented as strings. Date conversion uses the short date format based on system settings.
Converting to Boolean with CBool
The CBool function converts an expression to a Boolean subtype. It
returns True for non-zero numbers and non-empty strings. Empty strings, zero,
and Null convert to False. This is useful for conditional evaluations.
Dim bool1, bool2, bool3, bool4
bool1 = CBool(1) ' Non-zero to True
bool2 = CBool(0) ' Zero to False
bool3 = CBool("Hello") ' Non-empty string to True
bool4 = CBool("") ' Empty string to False
WScript.Echo "bool1: " & bool1
WScript.Echo "bool2: " & bool2
WScript.Echo "bool3: " & bool3
WScript.Echo "bool4: " & bool4
This example shows how different values convert to Boolean. Notice how any non-zero number becomes True. String conversion depends on whether the string contains characters or is empty.
Converting to Date with CDate
The CDate function converts a valid date string or number to a Date
subtype. It recognizes various date formats based on system locale settings.
Invalid date strings cause runtime errors. This is essential for date processing.
Dim date1, date2, date3
date1 = CDate("April 15, 2025")
date2 = CDate("15/4/2025")
date3 = CDate("2:30:45 PM")
WScript.Echo "date1: " & date1
WScript.Echo "date2: " & date2
WScript.Echo "date3: " & date3
This example demonstrates converting different date and time strings. The function is flexible with input formats but requires valid dates. Time values can be converted separately or combined with dates.
Type Checking Functions
VBScript provides functions to check variable types before conversion. These
include IsNumeric, IsDate, IsArray, and
IsObject. They return True if the variable can be converted to the
specified type. This prevents conversion errors.
Dim check1, check2, check3
check1 = IsNumeric("123") ' True
check2 = IsDate("April 15") ' True
check3 = IsNumeric("ABC") ' False
WScript.Echo "IsNumeric('123'): " & check1
WScript.Echo "IsDate('April 15'): " & check2
WScript.Echo "IsNumeric('ABC'): " & check3
This example shows how to safely check types before conversion. These functions are valuable for validating user input or external data. They help write more robust scripts by preventing conversion errors.
Source
VBScript Conversion Functions Documentation
In this article, we have explored VBScript conversion functions in depth. From basic type conversions to advanced type checking, these functions are essential for reliable scripting. The examples demonstrate practical usage scenarios that you can adapt to your own projects. With this knowledge, you can handle data type conversions confidently in your VBScript programs.
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