Visual Basic for Applications (VBA) is a programming language that is commonly used within Microsoft Office applications, such as Excel, Word, and Access. One of the key features of VBA is its ability to automate tasks and connect with external applications through the CreateObject function. This function allows VBA to create an instance of an external application and manipulate it through VBA code. In this blog post, we will explore the syntax, arguments, examples, remarks, and important notes of the CreateObject function.
VBA CreateObject Function – Purpose, Syntax and Arguments
Syntax:
Dim object_variable As New ClassName Set object_variable = CreateObject(Class, ServerName)
As shown in the syntax above, the CreateObject function has two parameters – Class and ServerName. The Class parameter specifies the ProgID (Programmatic Identifier) or the application-specific moniker of the external application. The ServerName parameter is optional and specifies the name of the computer where the external application is running.
Arguments:
- Class: This is a required argument that specifies the ProgID or the moniker of the external application. For example, the ProgID for Microsoft Word is “Word.Application”.
- ServerName: This is an optional argument that specifies the name of the computer where the external application is running. It can be either the computer name or the IP address.
Example:
Dim WordApp As New Word.Application 'Creates an instance of Microsoft Word
Set WordApp = CreateObject("Word.Application")
WordApp.Visible = True 'Makes the Word application visible
WordApp.Documents.Add 'Adds a new document to the Word application
WordApp.Quit 'Quits the Word application
Set WordApp = Nothing 'Clears the object variable
Remarks:
- The CreateObject function can only be used to connect with COM (Component Object Model) objects.
- COM objects are created with a GUID (Globally Unique Identifier) that helps identify and access them.
- If the optional ServerName parameter is not specified, the CreateObject function creates the object on the local computer.
- The object created using the CreateObject function will remain in memory until it is either closed or the connection is terminated through VBA code.
Important Notes:
- The CreateObject function is not limited to Microsoft Office applications but can be used to automate any external applications that have a COM interface.
- When using the CreateObject function, it is recommended to declare and assign it to an object variable. This allows for better control and management of the external application.
- The CreateObject function can be used to automate tasks such as creating new documents, updating data, and even interacting with user interfaces of external applications.
- If the specified external application is not registered on the computer, the CreateObject function will result in an error.
The CreateObject function is a powerful feature of VBA that allows for the automation and connection of external applications. By understanding its syntax, parameters, and best practices, VBA users can efficiently incorporate the CreateObject function into their code.
Understanding VBA CreateObject Function with Examples
Example 1: Creating an Excel Application Object
The CreateObject function in VBA is a powerful tool used to create an instance of an application or object. This function can be particularly useful when working with multiple applications or when needing to interact with programs outside of VBA. In this example, we will use the CreateObject function to create an Excel Application object.
Sub createExcelApp()
' Declare a variable to store the Excel Application object
Dim excelApp As Object
' Use the CreateObject function to create an instance of Excel
Set excelApp = CreateObject("Excel.Application")
' Display a message with the application version
MsgBox "Excel version: " & excelApp.Version
' Don't forget to close the application
excelApp.Quit
End Sub
The first line of code declares a variable named excelApp as an object. This variable will be used to store the Excel Application object that is created. Next, we use the CreateObject function and pass the application name “Excel.Application” as an argument. This tells VBA to create an instance of the Excel application. The Set keyword is used to assign the object to our excelApp variable.
Once the object is created, we can use it to perform actions on the Excel application. In this example, we use the Version property to retrieve the version of Excel that is open. After displaying the version in a message box, we use the Quit method to close the Excel application. This is an important step to ensure that the application is not left open and running in the background.
In summary, the CreateObject function is used to create an instance of an application or object. By specifying the application name as an argument, we can create an instance and use it to perform tasks within that application.
Example 2: Creating a Word Document Object
Similar to the previous example, we can also use the CreateObject function to create a Word Document object. This allows us to open a document and manipulate it using VBA.
Sub createWordDoc()
' Declare a variable to store the Word Document object
Dim wordDoc As Object
' Use the CreateObject function to create an instance of Word
Set wordDoc = CreateObject("Word.Application")
' Create a new document
wordDoc.Documents.Add
' Add text to the document
wordDoc.ActiveDocument.Content.InsertAfter ("This is a new Word document created using VBA.")
' Save and close the document
wordDoc.ActiveDocument.SaveAs "C:\Users\User\Desktop\VBA Document.docx"
wordDoc.Quit
End Sub
In this example, we declare a variable named wordDoc as an object and use the CreateObject function to create an instance of Word. Next, we use the Add method to create a new document and then use the InsertAfter method to add text to the document.
Finally, we use the SaveAs method to save the document to a specific location on our computer and then use the Quit method to close the Word application. This is an important step to ensure that the document is saved and the application is closed properly.
This example demonstrates how the CreateObject function can be used to interact with a different application and perform tasks within it.
Example 3: Creating a FileSystemObject
Apart from creating an instance of an application, the CreateObject function can also be used to create an instance of a FileSystemObject. This allows us to perform tasks related to files and folders on our computer.
Sub createFileSystemObject()
' Declare a variable to store the FileSystemObject
Dim fso As Object
' Use the CreateObject function to create an instance of the FileSystemObject
Set fso = CreateObject("Scripting.FileSystemObject")
' Check if a file exists
If fso.FileExists("C:\Users\User\Desktop\VBA Document.docx") Then
MsgBox "The document exists."
Else
MsgBox "The document does not exist."
End If
' Check if a folder exists
If fso.FolderExists("C:\Users\User\Desktop\VBA Folder") Then
MsgBox "The folder exists."
Else
MsgBox "The folder does not exist."
End If
' Don't forget to set the object to Nothing when done using it
Set fso = Nothing
End Sub
In this example, we use the CreateObject function to create an instance of the FileSystemObject, which will allow us to check if a specific file and folder exist on our computer. The code checks for the existence of the VBA Document and VBA Folder and displays a message accordingly.
It is important to note that the FileSystemObject should be set to Nothing when we are done using it to release memory resources. This is done in the last line of code in this example.
The above examples demonstrate how the CreateObject function can be used to create an instance of an application, a document, and a FileSystemObject. This function is flexible and can be used to interact with different applications and objects within VBA.
Conclusion
The CreateObject function is a powerful tool in VBA that allows us to create an instance of an application or an object. In this blog post, we explored how this function can be used to create an Excel Application object, a Word Document object, and a FileSystemObject. By understanding how to use this function, we can expand our capabilities in VBA and interact with different programs and files.
