User Extensibility and Customization

Custom Mappings Extensibility

This approach allows VB6 AI Migrator users to specify customized mappings.  The users can decide which elements to transform and what transformation to apply. Even though only simple mappings are allowed in this solution, the capabilities of this feature have been enough for some VB6 AI Migrator clients to specify around 20,000 customized mappings on their own and apply them successfully.

The custom mappings extensibility is even more powerful when combined with the development of custom helper classes. The helper classes can provide equivalent behavior when some functionality is not available in the target platform.

Custom Maps Editor

The custom maps editor is implemented as a VB6 AI Migrator Plug-in. It can be found under the tools menu in the main window of the VB6 AI Migrator’s GUI.

The controls placed on the editor provide the following functionalities:

Action	Icon	Description
New		Creating a New custom map configuration. When the user selects this option, he/she is prompted for a new configuration name and description.  Figure 1. Input dialog for entering new custom maps file configuration name
Save		Saving the current map configuration
Save As		Save the current configuration with a new name. When this option is selected, the user is prompted for a new name for the custom map configuration copy that will be created.   Figure 2. Input dialog for new name
Delete		Delete the currently selected configuration. The user will be prompted for confirmation before actually removing the file.

Writing a new Custom Map File

Custom Maps are written for Types or Members.
A Type is either:

• a Class
• a Form
• a Module
• an Enumeration

And a Member is either:

• Any Class Property, Sub or Function
• Any Form Property, Sub or Function
• Any Module Sub or Function
• Any Enumeration’s Field

A custom map applies for both references and declarations of the given element. In order to get familiarized with the custom maps editor some of the most used concepts are described below.

References

A reference is any use of a Type or a Member in your code. Examples of Type references are:

[VB6]

Dim x as Class1
Sub foo(x as Class1)
End Sub

Examples of Member references are:

[VB6]

Sub Foo(x as Class1)
x.Member1
Dim a
A = Enum1.Value1
End Sub

Declarations

A declaration is the code segment where the element definition is located.

Visibility

The custom maps feature can change the visibility of a given element in the target code. The new visibility modifier can be set to:

• Public
• Private
• Protected
• Internal

Target Return

The target return is the data type for subs, properties and functions to be returned to the code flow path after the execution of this code segment. The user cannot change the type of an enum or any enum field.

Note that if the user changes the return type of a function, it can result in some compilation errors.

VB6 Project

The VB6 argument of the custom maps editor is used if a multi-project upgrade is being performed, so the user can specify the particular project to apply the custom mappings in order to avoid name conflicts and to fine tune de transformations scope and precision.

About removals

Performing removals of code elements can have severe implications; it is not safe unless the code elements are not referenced by any other code segment in the current project, or in other VB6 projects if a multi-project upgrade is performed.

Sub, Properties or Function removals

This kind of removals can produce compilation errors if any of these elements are used or referenced. Also, if these element were part of a more complex statement like an If expression, the upgrade engine will remove the complete instruction, possibly deleting important code.

Properties are removed as a whole code segment, which means that the user cannot specify to remove only the get or set of a property.

Enumerations

Removing enumeration elements can affect the values of the rest of the elements in the entire enumeration, which can affect the normal program execution flow.

Using the Editor

The ComboBox in the top right corner allows you to change between current configurations. The custom map files are edited in a grid control. The user can navigate through the columns with the arrows keys.

Grid Control Columns

Column Name	Description
VB6 Project Name	The particular VB6 project name should be specified here
SourceName	This is the “complete name” of a given element. The complete name has the following format: <Class/Module/Form/Enum name>.<Member name>
MapType	Choose between Member (default) or Type.
New Reference Name	Only set it if the user reference action is “Modify”. It’s the new name that will be used for all references
Reference Action	Choose between Leave, Modify or Remove
New Declaration Name	Only set it if the user declaration action is Modify. This will be used as the new name for the element declaration
Declaration Action	Choose between Leave, Modify or Remove
Visibility	Choose between Nothing (default), Public, Private, Protected or Internal
Target Return	This applies for Properties and Functions, and it changes the return type. This setting is ignored for Types and for enumeration fields