GetObject Fails while CreateObject Works

Question

I recently got a small CG software package from my friend his father wrote about 30 years ago. It has a window where one can create and render some solid primitives. Interestingly, it has a VBA interface and I can in Excel (let’s call it TheSoftware) use Set app = CreateObject(“TheSoftware.Application”) to create such application (after setting app.Visible to True one can get the window on the screen)! However, the GetObject(, “TheSoftware.Application”) returns the “ActiveX component can’t create object” error. More surprisingly to me, the GetObject(“”, “TheSoftware.Application”) successfully creates the application! I have its source code in C++ about 900 KB that I can share, but just to be quick, has anyone had this issue before, or have a clue what may be the issue? I am no expert in C++, and the author passed away 4 years ago. I have seen the “opposite” problem of failing to create an object but OK when getting it, but not this one. Any idea is welcome, thanks!

Answer 1

GetObject(FName) opens a file or connects to a file if it already opened (and if class is specified use that class to open it) OR GetObject(,"Appname") connects to a running instance of an application. You are creating a blank file.

Visual Basic Scripting Edition

GetObject Function

See Also CreateObject Function

Requirements

Version 5

Returns a reference to an Automation object from a file.

GetObject([pathname] [, class])

Arguments

pathname

Optional; String. Full path and name of the file containing the object to retrieve.

If pathname is omitted, class is required.

class

Optional; String. Class of the object.

The class argument uses the syntax appname.objectype and has these parts:

Use the GetObject function to access an Automation object from a file and assign the object to an object variable. Use the Set statement to assign the object returned by GetObject to the object variable. For example:

Dim CADObject
Set CADObject = GetObject("C:\CAD\SCHEMA.CAD")

When this code is executed, the application associated with the specified pathname is started and the object in the specified file is activated. If pathname is a zero-length string (""), GetObject returns a new object instance of the specified type. If the pathname argument is omitted, GetObject returns a currently active object of the specified type. If no object of the specified type exists, an error occurs.

Some applications allow you to activate part of a file. Add an exclamation point (!) to the end of the file name and follow it with a string that identifies the part of the file you want to activate. For information on how to create this string, see the documentation for the application that created the object.

For example, in a drawing application you might have multiple layers to a drawing stored in a file. You could use the following code to activate a layer within a drawing called SCHEMA.CAD:

Set LayerObject = GetObject("C:\CAD\SCHEMA.CAD!Layer3")

If you don't specify the object's class, Automation determines the application to start and the object to activate, based on the file name you provide. Some files, however, may support more than one class of object. For example, a drawing might support three different types of objects: an Application object, a Drawing object, and a Toolbar object, all of which are part of the same file. To specify which object in a file you want to activate, use the optional class argument. For example:

Dim MyObject
Set MyObject = GetObject("C:\DRAWINGS\SAMPLE.DRW", "FIGMENT.DRAWING")

In the preceding example, FIGMENT is the name of a drawing application and DRAWING is one of the object types it supports. Once an object is activated, you reference it in code using the object variable you defined. In the preceding example, you access properties and methods of the new object using the object variable MyObject. For example:

MyObject.Line 9, 90
MyObject.InsertText 9, 100, "Hello, world."
MyObject.SaveAs "C:\DRAWINGS\SAMPLE.DRW"

Note Use the GetObject function when there is a current instance of the object or if you want to create the object with a file already loaded. If there is no current instance, and you don't want the object started with a file loaded, use the CreateObject 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. With a single-instance object, GetObject always returns the same instance when called with the zero-length string ("") syntax, and it causes an error if the pathname argument is omitted.

Requirements Version 5

See Also CreateObject Function

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Build: Topic Version 5.6.9309.1546

Also these are the COM API calls that each form makes. From the Automation part of the COM docs.

CreateObject (“ProgID”)

• CLSIDFromProgID

• CoCreateInstance

• QueryInterface to get IDispatch interface.

GetObject (“filename”, “ProgID”)

• CLSIDFromProgID

• CoCreateInstance

• QueryInterface for IPersistFile interface.

• Load on IPersistFile interface.

• QueryInterface to get IDispatch interface.

GetObject (“filename”)

• CreateBindCtx creates the bind context for the subsequent functions.

• MkParseDisplayName returns a moniker handle for BindMoniker.

• BindMoniker returns a pointer to the IDispatch interface.

• Release on moniker handle.

• Release on context.

GetObject (“ProgID”)

• CLSIDFromProgID

• GetActiveObject on class ID.

• QueryInterface to get IDispatch interface.

Dim x As New interface

• Find CLSID for interface.

• CoCreateInstance

• QueryInterface