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Introduction |
ASP Migration to ASP.NET
Published on 09/07/01
Nobody expects the Spanish Inquisition
ASP.NET is not light work, I've
been reading two books at the same time, one on ASP 3 and the other on ASP.NET
and its like learning two different languages (VBScript and VB.NET) and I
found that treating them as different makes it easy to learn the language
(from now on when I refer to language it mean VB.NET being use in ASP.NET) and
adapt it to my old applications. This article will not touch all the changes
(the changes from Beta 1 to Beta 2 are many many many pages alone) but I want
to give you a look at what to expect.
The one thing I hate
I have read multiply books on ASP
and I am very very pissed off about the following statement being used -
Do you see it? When calling a
method ALWAYS use brackets for the parameters. I always have and its very good
practice and makes code more readable, ASP.NET has finally put a stop the
madness of this by forcing people to use -
And its about time too.
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This isn't VBScript |
Its VB not VBScript
VB.NET isn't the next version of
VBScript (that's out the window), its VB, that means that you can take a VB.NET
application and plonk it into an ASP.NET page with minor problems. It also
allows more functionality in the script and use of some more advanced
functionality
Class Animal private species as
string private id as integerSub
change_stuff(a as string, optional b as integer = 0) If Len(id) Then id =
b species = a End Sub End Class
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I don't think I've ever seen a class in ASP, or
the keywords - public and private used. This opens up much more space for
people to create custom types without the use of an object. The optional
keyword is also something new. I once read an ASP tutorial where the author
wrote all the code in VB and then told us how to change it to ASP, that was
not only terrible but I first saw the optional keyword and thought that it
would be great, its like in C++. Now we can specify optional parameters (with
default values) and use them. I can then do the following.
Dim wolf as New Animal Dim
panda as New Animal
wolf.change_stuff("Canis rufus", 2)
panda.change_stuff("Ailuropoda melanoleuca") |
This gives makes
wolf.species = "Canis rufus" wold.id = 2
and panda.species = "Ailuropoda melanoleuca"
panda.id = 0. Also check out the New
keyword being used. This replaces the set keyword in ASP. Instead of -
Set objConn =
Server.CreateObject("ADODB.Connection") |
We use -
Dim objConn as new
OleDBConnection([Connection String and other parameters]) |
Basically nearly all of VB.NET's functionality
rubs off on ASP.NET as well, there may be a few things such as forms to deal
with.
There are also many more things of VB.NET that
is very useful in ASP.NET such as the try...catch...finally statement. This
allows you to try to perform a task, catch any errors and handle them. I will
discuss this in more detail in my exception's in ASP.NET article.
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Web Forms |
Web Forms
You've probably heard of these if you've done
research into ASP.NET, they are a bit complicated at first and I think I'm
getting OOS (or RSI) from writing
runat=server constantly. But they do
provide a lot of new features (see my DataGrid's in ASP.NET), although a
DataGrid isn't in a form tag its still one of those new GUI things that are
built in. VB6 people will remember DataGrids and these are very similar. It
allows dynamic things to happen with your form elements. The new GUI controls
(well they produce GUI elements like tables) are much better that conventional
ways, see my BDP article for the table and then the DataGrid's in ASP.NET
article and check out the difference. I won't go into it too much, but I'll
give you an example -
<form runat=server>
<asp:textbox id="name" ontextchanged="name_change()"
runat=server />
<asp:button id="submit" runat=server />
</form> |
This creates a textbox and a button that were
generated on the server, they
ontextchanged property allows me to execute
server-side functions or events like with the client-side version, but this
time it can perform more advanced things. The
ontextchanged
happens when we submit the form, the action by default it to post back to the
page and any events are handled on the page. (
name_change()
is a method on the page).
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ADO.NET |
ADO.NET
ADO.NET is the next version of ADO, there isn't
much difference, but there is a huge lean towards SQL Server. There are new
ADO objects, connectors, commands, adaptors, etc. and there is an exact
duplicate for the SQL Server versions, the SQL Server versions are said to
provide more functionality for SQL Server and let it open up its features with
XML and all that, I think its just bias to their only database server. There
is also a lot of stuff to do with data storage and greater support in VS.NET
for these new tools. They can make the access a bit longer, as filling a
dataset requires a data adapter, a data connection and usually a data command.
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Web Services |
Web Services
Web services may be a replacement to
components, then again, maybe not. Web Services are very similar to
components, you create functions and classes and other stuff in VB/C#/Any .NET
language and then you just make the things that you want available to the web.
MSDN's .NET show has a show where they create a web service and make it
available to people, its very good if you are new to .NET available at -
http://msdn.microsoft.com/theshow/Episode013/default.asp,
I actually learnt a lot from just watching this episode.
A web service basically gets information and
then churns out something (not always) in XML, this data could be a dataset or
a string manipulation event may occur. Components however are a bit different
as they are a whole application in one, web services I don't see as being an
application as much an information provider. Components however are being
taken over by these new web services, although I don't like it, it may be wise
to think about how to do your old stuff in the new web service way. I plan to
do an article on web services, but its quite hard to explain.
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Additional Reading |
Where now?
Here we have only scratched the surface of
ASP.NET, the whole .NET platform is huge and Microsoft has provided a wealth
of information on it, I like to use the .NET show best because I respond best
to a visual approach. Here are some episodes that I like :
-
http://msdn.microsoft.com/theshow/Episode013/default.asp -
Creating a simple .NET subscription service using ASP.NET and web services.
-
http://msdn.microsoft.com/theshow/Episode009/default.asp -
ASP.NET, what it is and changes from ASP 3
-
http://msdn.microsoft.com/theshow/Episode011/default.asp - .NET,
what is .NET
-
http://msdn.microsoft.com/theshow/Archive.asp
- Archives of the show, the most recent ones have information on VB.NET and
VS.NET\
I hope that I have given you some more insight
into ASP.NET and what changes it will involve for developers. A great option
is to get a book on .NET (see related articles), or a book specifically on
ASP.NET (see upcoming articles). I hope that I have left you with some
information that will be worthwhile to you in what will come.
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