VBA CStr Function

The CStr function is a useful built-in function in VBA (Visual Basic Applications) that converts a value or expression into a string data type. The term “CStr” stands for “Convert to String”. This function is often used in conjunction with other string handling functions to manipulate and format values stored in variables.

VBA CStr Function – Purpose, Syntax and Arguments

Syntax:

CStr(expression)

Arguments:

• expression: This is required and can be any valid expression that you want to convert to a string. It can be a numeric, date, or boolean value, or even a variable or function that returns a value.

Example:

Let’s take a look at a simple example to understand how the CStr function works.

Dim num As Integer
num = 123
MsgBox "The number " & CStr(num) & " was converted to string."

In this example, we declared a variable “num” and assigned it a value of 123. Then, using the CStr function, we converted the numeric value into a string and concatenated it with a text message. The resulting message box would display: “The number 123 was converted to string.”

Remarks:

• The CStr function is commonly used in VBA to convert numeric values to strings because it offers more control and precision than other methods, such as the Format function.
• If the expression you provide to the CStr function contains a null or empty value, it will return an empty string (“”).
• The CStr function can also be used to convert string values to strings, but it will not make any changes to the string itself.

Important Notes:

• The CStr function does not modify the original value or variable, it simply returns a string representation of it.
• When using the CStr function, it is important to remember that it only converts the first valid expression in a variable. For example, if your variable contains multiple values separated by a comma, only the first value will be converted to a string.
• If you need to convert an entire array of values to strings, you can use the Join function together with the CStr function.

The CStr function is a powerful tool in VBA that allows you to easily convert various data types into a string data type. It can be especially useful when working with user input, as it ensures that the values are formatted correctly for further manipulation. So, the next time you need to convert a value to a string, remember to use the CStr function for a seamless conversion process.

Understanding VBA CStr Function with Examples

Convert Numeric Value to String

Description:
The CStr function in VBA is used to convert a numeric value to a string. It takes a numeric value as an input and returns a string that represents the input number. This is useful when working with different types of data in VBA, as it allows you to easily convert between numeric and string values.

Dim numValue As Integer
numValue = 123
Dim strValue As String
strValue = CStr(numValue)
'displays "123" as a string
MsgBox strValue

Explanation:

1. First, we declare a variable numValue of type Integer and assign it a numeric value of 123.
2. Next, we declare a variable strValue of type String, which will hold the converted value.
3. Using the CStr function, we convert the numeric value numValue to a string and assign it to the variable strValue.
4. Finally, we use the MsgBox function to display the value of strValue as a string, which in this case is “123”.

This example demonstrates how the CStr function can be used to convert a numeric value to a string, which can then be easily manipulated and used in various VBA operations.

Concatenating Strings

Description:
CStr function can be used to concatenate strings in VBA. When used with the & operator, the CStr function converts a numeric value to a string and then joins it with other strings, creating a single concatenated string.

Dim numValue As Integer
numValue = 123
'displays "The number is 123"
MsgBox "The number is " & CStr(numValue)

Explanation:

1. First, we declare a variable numValue of type Integer and assign it a numeric value of 123.
2. Next, we use the MsgBox function to display a message, along with the concatenated value of CStr(numValue).
3. The & operator is used to concatenate the string “The number is ” with the converted value of numValue (which is “123” in this case).
4. The end result is a single string, “The number is 123”, which is displayed in the message box.

This example shows how the CStr function can be used to convert a numeric value to a string and concatenate it with other strings, making it useful for creating custom messages or labels in VBA.

Converting Dates to Strings

Description:
The CStr function can also be used to convert dates to strings in VBA. When dealing with dates in VBA, it is important to ensure that they are in the correct format. The CStr function allows you to specify the desired format in which you want the date to be displayed as a string.

Dim myDate As Date
myDate = #12/31/2021#
Dim strDate As String
strDate = CStr(myDate)
'displays "12/31/2021" as a string
MsgBox strDate
strDate = CStr(myDate, "mmm/dd/yyyy")
'displays "Dec/31/2021" as a string
MsgBox strDate

Explanation:

1. First, we declare a variable myDate of type Date and assign it a date value of December 31, 2021.
2. Next, we use the CStr function to convert the date value to a string and assign it to the variable strDate.
3. The default format for dates in VBA is mm/dd/yyyy, so when the CStr(myDate) is displayed using the MsgBox function, it shows up as “12/31/2021”.
4. In the second part of the code, we use the optional parameter of the CStr function to specify a different format for the date string, in this case mmm/dd/yyyy, which results in “Dec/31/2021”.

This example shows how the CStr function can be used to not only convert a date to a string, but also allow you to choose the format in which the date is displayed, making it useful for displaying dates in different formats in VBA applications.

Converting Boolean Values to Strings

Description:
In VBA, boolean values are binary values that can only have two states – True or False. The CStr function can be used to convert these values to strings, which can be helpful when working with conditional statements or error handling.

Dim answer As Boolean
answer = True
If answer = True Then
'displays "The answer is True"
MsgBox "The answer is " & CStr(answer)
End If
Dim errorFound As Boolean
errorFound = False
If errorFound = False Then
'displays "No error found. Status: False"
MsgBox "No error found. Status: " & CStr(errorFound)
End If

Explanation:

1. First, we declare a boolean variable answer and assign it a value of True.
2. Next, we use the If statement to check if the value of answer is True, and then use the CStr function to convert it to a string and display it in the message box.
3. In the second part of the code, we declare another boolean variable errorFound and assign it a value of False.
4. Using the If statement again, we check if the value of errorFound is False, and then display a message using the CStr function to convert the boolean value to a string.

This example shows how the CStr function can be useful in handling boolean values in VBA, as it allows you to easily convert them to strings for display purposes.

Handling Errors with CStr

Description:
The CStr function can also be used in error handling in VBA. When working with large datasets or complex calculations, errors are bound to occur. The CStr function can be used to convert these errors to strings, making it easier to handle them and display relevant error messages to the user.

On Error GoTo errorHandler
Dim result As String
Dim x As Integer
x = 0
result = 12 / x
'displays "Infinity" (default value for division by zero error)
MsgBox result
Exit Sub
errorHandler:
'displays "An error occurred: 11 - Division by zero"
MsgBox "An error occurred: " & CStr(Err.Number) & " - " & Err.Description

Explanation:

1. We use the On Error statement to create an error handling block, telling VBA to go to a specific label if an error occurs.
2. We declare a string variable result, and an integer variable x and assign it a value of 0.
3. In the next line, we attempt to perform a calculation that will result in a division by zero error.
4. Instead of displaying the default value of “Infinity”, we use the CStr function to convert the error number and description to strings and display them in a custom error message.

This example demonstrates how the CStr function can be used in error handling to convert error values to strings, making it easier to display custom error messages to the user.

Conclusion

The CStr function in VBA is a useful tool for converting various types of data to strings. It allows you to easily manipulate and use different types of data in VBA, such as numeric values, dates, boolean values, and even error values. By understanding how the CStr function works and the different ways in which it can be used, you can become more proficient in writing VBA code and creating dynamic and user-friendly applications.