Vista - Multi - targeting not working properly.

Hello.

I recently started a WPF project in .NET 3.5. Since then I learned that the
target arhitecture does not support .NET 3.5, only .Net 3.0. I continued by
changing the target framework to .NET 3.0 in the project application
settings. Although all seemed fine on the development machine I since
realized that downgrading from .Net 3.5 to .NET 3.0 does nothing.

Once I deploy my application to a windows machine that only has .net 3.0 on
it, it would crash. Further investigation revield that downgrading from 3.5
to 3.0 somehow does not prevent you from using features only present in 3.5.

Do I have it all wrong?

I would really like to know. This does not seem like something that is hard
to test so I am unsure as to why multi targeting is so hyped when it is
actually useless.

Hello,
Nearly the only difference between 3.0 and 3.5 targeting projects is a reference
to the System.Core assembly (and a couple more, like MSBuild's, but that's
a rarer case). That's the thing to check.

C# language features do not depend on the target framework version and work
for 2.0/3.0/3.5 just as good.

(H) Serge

It makes sense to me that the language is compatible between the different
versions. However, what multi-targeting comes down to for me is the following:

A developer machine with .NET 3.5 installed being able to develop a .NET
program that would run on a OS with just .NET 3.0 installed.

For example:

I can compile and run WPF code simular to the following on a development
machine ( running .Net 3.5 ) set to target framework 3.0:

System.Windows.Controls.Button btn = new System.Windows.Controls.Button();
btn.Effect = null; // This should fail! Button.Effect does not exist in
framework 3.0

This code runs on the development machine.
This code does NOT run on a Machine with only .Net 3.0 installed. ( Or .net
3.0 SP1 for that matter, which should work according to the help file's
Framework supported list )

The issue is that the IDE must protect the developer against himself when
coding to a target framework lower than the maximum supported in his machine.
This does not happen which makes this targetting feature seem not very
usefull. I dont understand .NET well enough to understand why this is not
possible.

Does this make sense?

W










Dev

"Serge Baltic" wrote: