Implementing a Field

The other member from an interface that can be implemented is the field. The field in the interface is declared as any other public field, but in the implementing class it must be a property (with get and let/set).

Upgrading to Visual Basic .NET implies converting the field to a property in the interface and keeping it in the class. It means the field in the interface must be converted to a property with a get and set with the same name and type. The property in the class follows the same rules as the properties in the previous section, but additionally in the CoClass class a field is added with the name <Field>_MemberVariable to store the value from the property.

For C#, the rules are similar to Visual Basic .NET; the only difference is the renaming of the property name from <Interface>_<Property> to <Property>.

Original VB6 code

AnInterface.cls

Public mPhaseName As String

AClass.cls

Implements AnInterface
Public Property Get AnInterface_mPhaseName() As String
    ' Code
End Property
Public Property Let AnInterface_mPhaseName(ByVal v As String)
    ' Code
End Property

VB6 AI Migrator resulting VB.NET code

AnInterface.cls

Interface AnInterface
    Property mPhaseName As String
End Interface
Friend Class AnInterface_CoClass
    Implements AnInterface
            Dim mPhaseName_MemberVariable As String = ""
    Public Property mPhaseName() As String Implements AnInterface.mPhaseName
        Get
            mPhaseName = mPhaseName_MemberVariable
        End Get
        Set(ByVal Value As String)
            mPhaseName_MemberVariable = Value
        End Set
End Property
End Class

AClass.cls

Friend Class AClass
    Implements AnInterface
    Public Property AnInterface_mPhaseName() As String Implements AnInterface.mPhaseName
        Get
            ' Code
        End Get
        Set(ByVal Value As String)
            ' Code
        End Set
    End Property
End Class 

VB6 AI Migrator resulting C#.NET code

AnInterface.cls

    interface AnInterface
    {
        string mPhaseName{ get; set; }
    } 
    internal class AnInterface_CoClass
    : AnInterface
    {
            string mPhaseName_MemberVariable = String.Empty;
            public string mPhaseName
            {
                get
                {
                    return mPhaseName_MemberVariable;
                }
                set
                {
                    mPhaseName_MemberVariable = value;
                }
            }
    }

AClass.cls

    internal class AClass
    : AnInterface
    {
            public string mPhaseName
            {
                get
                {
                    // Code
                    return String.Empty;
                }
                set
                {
                    // Code
                }
            }
}