In Visual Basic 6.0, all members of a user-defined type (UDT) were initialized when they were declared inside the Type statement block.

In Visual Basic .NET, user-defined types are replaced by structures. Members that require parameterless constructors (such as fixed-length strings, fixed-size arrays, and variables declared with the New keyword) require initialization. During upgrade, an Initialize() subroutine is added to the structure. Calls to the Initialize subroutine must be added whenever the structure is declared.

When an array of structures is declared or redimensioned, the Initialize() subroutine has to be called for each element of the array, or some members of the structures will not be initialized as they were in Visual Basic 6.0.

What to do next

• Add a call to the Initialize() subroutine wherever the array is declared or redimensioned:
  ' After upgrade to Visual Basic .NET
  Private Structure MyStruct
     Dim MyClass1 As Class1
     
     ' UPGRADE_TODO: "Initialize" must be called to initialize instances of this structure.
     Public Sub Initialize()
        MyClass1 = New Class1
     End Sub
  End Structure
  
  Private Structure StructArray
     Dim MyArray As MyStruct
     
     ' UPGRADE_TODO: "Initialize" must be called to initialize instances of this structure.
     Public Sub Initialize()
        MyArray.Initialize
     End Sub
  End Structure
  
  Private Sub Form1_Load(ByVal eventSender As System.Object, ByVal eventArgs As System.EventArgs) Handles MyBase.Load
     ' UPGRADE_WARNING: Array MyStructArray may need to have individual elements initialized.
     Dim MyStructArray(1) as StructArray
     MyStructArray(0).MyArray.Initialize()
     MyStructArray(1).MyArray.Initialize()
  End Sub

See Also

Initialize must be called to initialize instances of this structure