PRB: Type Mismatch with Default Prop of VB4 Data Access Object

• Standard, Professional and Enterprise Editions of Microsoft Visual Basic, 16-bit and 32-bit, for Windows, version 4.0

SYMPTOMS

Some data access objects in Visual Basic for Windows version 4.0 no longer have the default "Name" property. Instead, these objects now have a default collection. This change can lead to "Type Mismatch" (Error 13) or "Invalid Argument" (Error 3001) errors when attempting to run your code.

WORKAROUND

To work around this problem, add the name of the property you want to reference.

For example, use this:

   MsgBox Data1.Database.TableDefs(0).Name

   MsgBox Data1.Database.TablesDefs(0)

MORE INFORMATION

If a data access object in Microsoft Visual Basic version 4.0 has a collection as a property, the collection is now the default property. There is no longer support for default properties on any objects except Field, Parameter and Property objects.

This is a change in behavior from Microsoft Visual Basic version 3.0 where the "Name" property was the default property for TableDef object.

Having a default collection allows the user to implement a short hand syntax for referencing into the collection.

For example, this:

   MsgBox Data1.Database.TableDefs(0).Fields(0).Name

   MsgBox Data1.Database.TableDefs(0)(0).Name