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Visual Basic for Applications Reference

Visual Studio 6.0

CreateObject Function

See Also    Example    Specifics

Creates and returns a reference to an ActiveX object.

Syntax

CreateObject(class,[servername])

The CreateObject function syntax has these parts:

Part Description
class Required; Variant (String). The application name and class of the object to create.
servername Optional; Variant (String). The name of the network server where the object will be created. If servername is an empty string (""), the local machine is used.

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.Application.Cells(1, 1).Value = "This is column A, row 1"
' Save the sheet to C:\test.xls directory.
ExcelSheet.SaveAs "C:\TEST.XLS"
' 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 a Excel.Application object:

Call MySub (CreateObject("Excel.Application"))

You can create an object on a remote networked computer by passing the name of the computer to the servername argument of CreateObject. That name is the same as the Machine Name portion of a share name: for a share named "\\MyServer\Public," servername is "MyServer."

Note   Refer to COM documentation (see Microsoft Developer Network) for additional information on making an application visible on a remote networked computer. You may have to add a registry key for your application.

The following code returns the version number of an instance of Excel running on a remote computer named MyServer:

Dim xlApp As Object
Set xlApp = CreateObject("Excel.Application", "MyServer")
Debug.Print xlApp.Version

If the remote server doesnt exist or is unavailable, a run-time error occurs.

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.

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