CreateObject Function
Description
Creates and returns a reference to an ActiveX object.
Syntax
CreateObject(class)
The class argument uses the syntax appname.objecttype and has these parts
| Part | Description |
|
| appname | Required; Variant (String). The name of the application providing the object. |
| objecttype | Required; Variant (String). The type or class of object to create. |
Remarks
Every application that supports Automation provides at least one type of object. For example, a word processing application may provide an Application object, a Document object, and a Toolbar object.
To create an ActiveX object, assign the object returned by CreateObject to an object variable:
' Declare an object variable to hold the object
' reference. Dim as Object causes late binding.
Dim ExcelSheet As Object
Set ExcelSheet = CreateObject("Excel.Sheet")
This code starts the application creating the object, in this case, a Microsoft Excel spreadsheet. Once an object is created, you reference it in code using the object variable you defined. In the following example, you access properties and methods of the new object using the object variable, ExcelSheet, and other Microsoft Excel objects, including the Application object and the Cells collection.
' Make Excel visible through the Application object.
ExcelSheet.Application.Visible = True
' Place some text in the first cell of the sheet.
ExcelSheet.Cells(1, 1).Value = "This is column A, row 1"
' Save the sheet to C:\test.doc directory.
ExcelSheet.SaveAs "C:\ TEST.DOC"
' Close Excel with the Quit method on the Application object.
ExcelSheet.Application.Quit
' Release the object variable.
Set ExcelSheet = Nothing
Declaring an object variable with the As Object clause creates a variable that can contain a reference to any type of object. However, access to the object through that variable is late bound; that is, the binding occurs when your program is run. To create an object variable that results in early binding; that is, binding when the program is compiled, declare the object variable with a specific class ID. For example, you can declare and create the following Microsoft Excel references:
Dim xlApp As Excel.Application
Dim xlBook As Excel.Workbook
Dim xlSheet As Excel.WorkSheet
Set xlApp = CreateObject("Excel.Application")
Set xlBook = xlApp.Workbooks.Add
Set xlSheet = xlBook.Worksheets(1)
The reference through an early-bound variable can give better performance, but can only contain a reference to the class specified in the declaration.
You can pass an object returned by the CreateObject function to a function expecting an object as an argument. For example, the following code creates and passes a reference to an Excel.Application object:
Call MySub (CreateObject("Excel.Application"))
Note Use CreateObject when there is no current instance of the object. If an instance of the object is already running, a new instance is started, and an object of the specified type is created. To use the current instance, or to start the application and have it load a file, use the GetObject function.
If an object has registered itself as a single-instance object, only one instance of the object is created, no matter how many times CreateObject is executed.
See Also
GetObject function, Set statement.
Example
This example uses the CreateObject function to set a reference (xlApp) to Microsoft Excel. It uses the reference to access the Visible property of Microsoft Excel, and then uses the Microsoft Excel Quit method to close it. Finally, the reference itself is released.
Dim xlApp As Object ' Declare variable to hold the reference.
Set xlApp = CreateObject("excel.application")
' You may have to set Visible property to True
' if you want to see the application.
xlApp.Visible = True
' Use xlApp to access Microsoft Excel's
' other objects.
xlApp.Quit ' When you finish, use the Quit method to close
Set xlApp = Nothing ' the application, then release the reference.