shift appl. VB6 --> .NET

[jens]

Hello NG,

This question regards a migration of a vb6 application to .NET

Since 2 years we develop and extend an administration/reporting
application
based on VB6, Crystal Reports 10 and MS SQL Server 2000 which is
including as well the control
of an Excel calculation module via COM.

Now this application should be shifted to .NET, for what we have now to
calculate the estimated amount of time / money for this.
Question is, how shall we procede in this to get a result which is as
closest to the reality as possible and which issues we have to pay
attention to?
As annotation I can say that this application is programmed object
oriented as much as it is possible in VB6.

In a little brainstorming I got up to now the following main points we
have to think about:

1. selection of the target language in .NET (c#,java,vb.NET)
--> which language has which advantages / reason to choose it
--> or is it only a matter of which language suits the most to the
programmers?
--> because at the end it is in any case translated into Intermediate
Language

2. can we use migration tools (converter and other tools)?

3. because .NET uses extended possibilities of object oriented
programming (z.B. real inheritance., polymorphism ..) we probably have
to do a refactoring

4. maybe the program design should be checked in general und maybe
modelled in a new way,
because we have the work of reprogramming anyway

5. is it possible to convert the application (half automatic - see
point 2) nearly 1:1
and to use it first like before, and then bit by bit to overwork the
parts (according to .NET's possibilities) which then are going to be
changed or to get new features in any case, (bit by bit refactoring)

6. is control of Excel via COM possible like up to now?

7. how is it going with the implementation of modules in other
languages
(e.g. time critical calculation routines programmed in C)
--> or is the only possibility for this, to program directly in the
Intermediate Language and compile it to native code?
Has anyone been doing this already and has faced problems, which
haven't been expected before?

This topic was initiated by the costumer, but the question remains, if
it's really necessary.
For me as a programmer/program designer I see as advantages mainly the
extended possibilities of object oriented programming, safe support of
the base technologies in future and a bigger and more flexible variety
of functions and features which his been up to now only available by
using 3rd party components or tricks with Windows API functions, as
well as I expect better support in creating installation packages and
automated documentation, which again is in VB6 only possible with
3rd party components in a proper way.

The general question is how long the DLL concept so far as well as the
COM technology and the used API function will still be supported,
meaning starting when we have to go to another technology
in any case.

Thanks for your help!

[Norman Yuan]

Depending on what the app does and how the VB6 app developed, mostly
"migrate" VB6 to .NET ="rewite" in .NET. If you have been developing in both
classical VB and .NET long enough, you can easily reach the same conclusion.

Here is a latest article from MS on this topic:

http://msdn.microsoft.com/vbasic/def...ationstrat.asp
<je**@e-sistrum.com> wrote in message
news:11**********************@g44g2000cwa.googlegr oups.com...

Hello NG,

This question regards a migration of a vb6 application to .NET

Since 2 years we develop and extend an administration/reporting
application
based on VB6, Crystal Reports 10 and MS SQL Server 2000 which is
including as well the control
of an Excel calculation module via COM.

Now this application should be shifted to .NET, for what we have now to
calculate the estimated amount of time / money for this.
Question is, how shall we procede in this to get a result which is as
closest to the reality as possible and which issues we have to pay
attention to?
As annotation I can say that this application is programmed object
oriented as much as it is possible in VB6.

In a little brainstorming I got up to now the following main points we
have to think about:

1. selection of the target language in .NET (c#,java,vb.NET)
--> which language has which advantages / reason to choose it
--> or is it only a matter of which language suits the most to the
programmers?
--> because at the end it is in any case translated into Intermediate
Language

2. can we use migration tools (converter and other tools)?

3. because .NET uses extended possibilities of object oriented
programming (z.B. real inheritance., polymorphism ..) we probably have
to do a refactoring

4. maybe the program design should be checked in general und maybe
modelled in a new way,
because we have the work of reprogramming anyway

5. is it possible to convert the application (half automatic - see
point 2) nearly 1:1
and to use it first like before, and then bit by bit to overwork the
parts (according to .NET's possibilities) which then are going to be
changed or to get new features in any case, (bit by bit refactoring)

6. is control of Excel via COM possible like up to now?

7. how is it going with the implementation of modules in other
languages
(e.g. time critical calculation routines programmed in C)
--> or is the only possibility for this, to program directly in the
Intermediate Language and compile it to native code?
Has anyone been doing this already and has faced problems, which
haven't been expected before?

This topic was initiated by the costumer, but the question remains, if
it's really necessary.
For me as a programmer/program designer I see as advantages mainly the
extended possibilities of object oriented programming, safe support of
the base technologies in future and a bigger and more flexible variety
of functions and features which his been up to now only available by
using 3rd party components or tricks with Windows API functions, as
well as I expect better support in creating installation packages and
automated documentation, which again is in VB6 only possible with
3rd party components in a proper way.

The general question is how long the DLL concept so far as well as the
COM technology and the used API function will still be supported,
meaning starting when we have to go to another technology
in any case.

Thanks for your help!