VBA FreeFile Function

The VBA FreeFile function is a built-in function that is used to obtain a unique number for a file that can be used to reference a file opened by the FileOpen statement. This function is commonly used in Microsoft Excel and other Microsoft Office applications that use Visual Basic for Applications (VBA) to automate tasks.

VBA FreeFile Function – Purpose, Syntax and Arguments

Purpose:

The purpose of the FreeFile function is to generate a number that can be used to reference a file opened with the FileOpen statement. This function is commonly used in VBA code that deals with reading and writing files to perform tasks such as data import and export, data backup, and file manipulation.

Syntax:

FreeFile([rangenumber])

Arguments:

rangenumber (Optional): A number from 1 to 255, inclusive, that specifies the range from which the next free file number is to be returned. If omitted, a number from 1 to 255 is returned. If specified as 1, a number from 1 to 255 is returned. If specified as 2, a number from 256 to 511 is returned.

Example:

Suppose we have a text file named “data.txt” that contains the following data:

Name, Age, Gender
John, 25, Male
Mary, 30, Female
Tom, 28, Male

And we want to import this data into an Excel worksheet using VBA. We can use the FreeFile function to obtain a file number and then use the FileOpen statement to open the text file for reading. We can then use the Input function to read each line of data and split it into columns.

Sub ImportData()
Dim inputFile As Integer
Dim strLine As String, strData() As String
'get a file number
inputFile = FreeFile
'open the text file for reading
FileOpen inputFile, "data.txt", OpenMode.Input
Do While Not EOF(inputFile)
'read each line of data
strLine = LineInput(inputFile)
'split the line into columns
strData = Split(strLine, ",")
'write the data to the worksheet
Range("A" & Rows.Count).End(xlUp).Offset(1).Resize(1, 3).Value = strData
Loop
'close the file
FileClose inputFile
End Sub

In this example, we first use the FreeFile function to obtain a file number, which is stored in the “inputFile” variable. We then use the FileOpen statement to open the “data.txt” file for reading. Inside the Do Loop, we use the LineInput function to read each line of data and the Split function to split the line into columns. The data is then written to the Excel worksheet using the Range object. Finally, we close the file using the FileClose statement.

Remarks:

• The file number returned by the FreeFile function is an integer in the range from 1 to 255.
• This function can be called multiple times within the same procedure to obtain different file numbers.
• It is important to remember to close the file using the FileClose statement after using the FreeFile function. Failure to do so can result in open file handles, which can lead to errors or performance issues.
• The file number returned by the FreeFile function is only valid for use with the FileOpen statement. It cannot be used as an argument for other file-related functions, such as Seek or FileLen.

Important Notes:

• FreeFile is a built-in function in VBA and does not require any external libraries or add-ins.
• The file number returned by the FreeFile function is unique within a particular VBA project, but it may not be unique across different VBA projects or applications.
• The file number returned by the FreeFile function is not related to the actual file name or path. It only serves as a reference to the file within the VBA code.

Conclusion:

In conclusion, the VBA FreeFile function is a useful tool for interacting with files in VBA projects. By providing a unique file number, it allows us to easily reference and manipulate files using various VBA functions and statements. It is important to remember to close the file after using the FreeFile function to avoid any potential errors. This function is widely used in Microsoft Office applications and can greatly enhance the automation and efficiency of tasks involving file manipulation.

Understanding VBA FreeFile Function with Examples

Creating a New File using FreeFile Function

The FreeFile function is a useful tool in VBA for creating a new file or getting an unused file number for a file that is already open. This function returns an integer value which can be used as a file number in the Open statement to access the file. Let’s look at an example of how to create a new file using FreeFile function.

Sub CreateNewFile()
Dim fileNum as Integer
fileNum = FreeFile
'Open the file in write mode
Open "C:\Users\Documents\NewFile.txt" For Output As #fileNum
'Write data to the file
Write #fileNum, "This is a new file created using VBA"
'Close the file
Close #fileNum
End Sub

• First, we declare a variable “fileNum” of the type Integer to store the value returned by the FreeFile function.
• Next, we call the FreeFile function and assign the returned value to the “fileNum” variable. This value will be an integer that represents an unused file number.
• Then we use the Open statement to open the file “NewFile.txt” in write mode using the file number obtained from the FreeFile function.
• After opening the file, we use the Write statement to write the text “This is a new file created using VBA” to the file.
• Finally, we close the file using the Close statement to release the file number and memory resources associated with it.

This is a simple example of how the FreeFile function can be used to create a new file in VBA. It is important to note that the file number returned by the FreeFile function is unique and cannot be reused until it is closed using the Close statement.

Using FreeFile in a Loop to Create Multiple Files

The flexibility of the FreeFile function makes it a powerful tool to use in a loop when creating multiple files. This can be useful when you need to save data from a loop into individual files without overwriting any of the files. Let’s see an example of how this can be achieved.

Sub CreateMultipleFiles()
Dim fileNum as Integer
Dim i as Integer
'Loop through a list of names
For i = 1 to 5
fileNum = FreeFile
'Open the file in write mode
Open "C:\Users\Documents\" & i & ".txt" For Output As #fileNum
'Write data to the file
Write #fileNum, "This is file number " & i
'Close the file
Close #fileNum
Next
End Sub

• In this example, we first declare a variable “fileNum” of the type Integer and a variable “i” to hold the loop counter.
• We then use a For loop to loop through a list of names (1 to 5 in this case).
• Inside the loop, we use the FreeFile function to get an unused file number and assign it to the “fileNum” variable.
• Then, we use the Open statement to open a file with the name “i.txt” in the specified directory. In each iteration of the loop, a different file will be created with the names 1.txt, 2.txt, 3.txt, and so on.
• Using the Write statement, we add some text to the file based on the loop counter to make each file unique.
• Finally, we close the file using the Close statement before the next iteration of the loop begins.

This example shows how the FreeFile function can be used in a loop to create multiple files without the need for manually assigning file numbers.

Reusing File Numbers using FreeFile Function

The FreeFile function also allows us to reuse file numbers by releasing it and obtaining a new unused file number. This can be helpful when you have a limited number of files to work with and need to close and reopen files multiple times. Let’s take a look at an example.

Sub ReuseFileNumber()
Dim fileNum as Integer
'Open the file in read mode
Open "C:\Users\Documents\MyFile.txt" For Input As #fileNum
'Read data from the file
Msgbox "Data from file: " & Input(LOF(fileNum), fileNum)
'Close the file
Close #fileNum
'Release the file number
fileNum = 0
'Obtain a new file number using FreeFile
fileNum = FreeFile
'Open the file again in append mode
Open "C:\Users\Documents\MyFile.txt" For Append As #fileNum
'Write data to the file
Write #fileNum, "New data added using FreeFile function"
'Close the file
Close #fileNum
End Sub

• We first declare a variable “fileNum” of the type Integer to hold the file number obtained from the FreeFile function.
• Then we use the Open statement to open the file “MyFile.txt” in read mode using the file number obtained from the FreeFile function.
• Using the Input function, we read the data from the file and display it in a message box.
• After that, we close the file using the Close statement to release the file number.
• Then we set the value of “fileNum” to 0 to indicate that the file number is no longer in use.
• We use the FreeFile function again to obtain a new unused file number and open the same file in append mode.
• Using the Write statement, we add new data to the file and close it.

This example shows how the FreeFile function can be used to reuse file numbers and avoid getting an error when trying to open a file that is already open.

Conclusion

The FreeFile function in VBA is a useful tool for working with files. It allows us to create new files, reuse file numbers, and easily handle multiple files in a loop. It is a simple and efficient way to manage files in VBA and can be used in various applications that require manipulation of files. By using the code examples provided above, you can better understand how to use the FreeFile function in your own VBA projects.