AppDomains and Assemblies

[Fred Mertz]

I'm working towards an MCTS cert and I'm having to learn a bunch of stuff
that I doubt I'd stumble across on my own. One such feature of .NET is
AppDomains; programatically creating new AppDomains and programmatically
loading/unloading assemblies in them.

Question:
What are some scenarios where I'd want to...
1 - programmatically create or destroy AppDomains
2 - load and unload assemblies in AppDomains?

Please note that I'm NOT asking *how* to do any of those things.

I'm wondering what sorts of "real world" programming problems I could solve
by doing those things. Is it primarily to conserve system resources
throughout the session of an application (i.e., load/unload on an as-needed
basis)?

Thanks!

 

[Mr. Arnold]

I'm working towards an MCTS cert and I'm having to learn a bunch of stuff
that I doubt I'd stumble across on my own. One such feature of .NET is
AppDomains; programatically creating new AppDomains and programmatically
loading/unloading assemblies in them.

Question:
What are some scenarios where I'd want to...
1 - programmatically create or destroy AppDomains
2 - load and unload assemblies in AppDomains?

Please note that I'm NOT asking *how* to do any of those things.

I'm wondering what sorts of "real world" programming problems I could
solve by doing those things. Is it primarily to conserve system resources
throughout the session of an application (i.e., load/unload on an
as-needed basis)?

http://www.google.com/search?hl=en&q=AppDomains+,net&btnG=Google+Search

 

[Chris Mullins [MVP]]

A good example is the forthcoming CLR Add-In Model:

http://blogs.msdn.com/clraddins/archive/2007/01/12/welcome-to-the-clr-add-in-team-blog.aspx
http://blogs.msdn.com/clraddins/arc...n-to-detect-add-in-failures-jesse-kaplan.aspx

 

[Fred Mertz]

Thanks for the link. I've never heard of this site "google.com" -
fascinating how it can give 407,000 irrellevant links in, like, nanoseconds.
Oh, wait, that's not google's fault... strike that...

 

[Mr. Arnold]

Thanks for the link. I've never heard of this site "google.com" -
fascinating how it can give 407,000 irrellevant links in, like,
nanoseconds. Oh, wait, that's not google's fault... strike that...

You know, you got to be a little creative and look for yourself. I can't
hold your hand.

<g>

 

[=?ISO-8859-1?Q?Arne_Vajh=F8j?=]

I'm working towards an MCTS cert and I'm having to learn a bunch of stuff
that I doubt I'd stumble across on my own. One such feature of .NET is
AppDomains; programatically creating new AppDomains and programmatically
loading/unloading assemblies in them.

Question:
What are some scenarios where I'd want to...
1 - programmatically create or destroy AppDomains
2 - load and unload assemblies in AppDomains?

Please note that I'm NOT asking *how* to do any of those things.

I'm wondering what sorts of "real world" programming problems I could solve
by doing those things. Is it primarily to conserve system resources
throughout the session of an application (i.e., load/unload on an as-needed
basis)?

There are one very well known app that has that
capability: ASP.NET engine.

You will also need it if you need to create a server app that are
capable of loading and unloading plugins dynamicly.

The need to unload is usually not to save resources, but to be
able to load a new version of the same stuff.

Arne

 

[Fred Mertz]

RE:

<< I can't hold your hand.>>

Yah yah yah, I was just hoping Pamela Anderson (no, strike that- Danica
Patric) would show up to do that...

I "get" your point - google would be the go-to choice if I were needing to
know "what" an AppDomain is and how to programmatically create one and load
assemblies into it...

But my OP was specifically about some scenarios in which I'd actually want
to do such things. Perhaps I should have been a bit more specific... I've
been programming for over 14 years (granted it's all been in dBase III) and
I haven't yet come across a need to dynamically load or unload libraries.
Being that I'm quite aware that I don't know everything, I figured I'd ask
some of you who may have come across a "real world" need to do these things.

Bob (I mean Fred).

 

[Mr. Arnold]

RE:

<< I can't hold your hand.>>

Yah yah yah, I was just hoping Pamela Anderson (no, strike that- Danica
Patric) would show up to do that...

You're quite the joke-ster. But if you're looking for the woman above to be
out here on the Internet to hold you, then you may have some problems you
don't recognize.

I "get" your point - google would be the go-to choice if I were needing to
know "what" an AppDomain is and how to programmatically create one and
load assemblies into it...

Now, that I see what you're talking about, then according to what I just
read, because I got 70-536 book too, but I have been procrastinating about
getting there, I can see use for Appdomain.

But my OP was specifically about some scenarios in which I'd actually want
to do such things. Perhaps I should have been a bit more specific... I've
been programming for over 14 years (granted it's all been in dBase III)
and I haven't yet come across a need to dynamically load or unload
libraries. Being that I'm quite aware that I don't know everything, I
figured I'd ask some of you who may have come across a "real world" need
to do these things.

I try to get in the ballpark first as to why, and then I'll come up with my
own needs as to why I would use it. But I got to recognize why I would need
it first.

http://www.codeproject.com/dotnet/AppDomainMemImprovement.asp

You venture to guess how I got that link?

 

[Fred Mertz]

RE:

<< You venture to guess how I got that link >>

Sigh.

Goooooooogle

The problem with google is that, at least for this type of question, it
returns a bunch of articles that rehash the MSDN documentation. That is,
practically everything I've found (and YES, I have googled this, believe it
or not), is that the articles tell us (1) what an appDoman or assembly is;
(2) how to programmatically create/destroy appDomans; and (3) how to
programmatically load/unload assemblies.

Again, I'm not after that knowledge. I already know how to do all that.
Well, at least 70% of the time you if give me a multiple choice question I
can identify the "best" alternative.

I was simply wondering what are some real-world applications of this .NET
feature. Thus the OP... me trying to find out what some other professionals
are _actually_ using these features for.

 

[Mr. Arnold]

I was simply wondering what are some real-world applications of this .NET
feature. Thus the OP... me trying to find out what some other
professionals are _actually_ using these features for.

I have been programming professionally, since 1980, and I have been
programming on the Windows platform since 1996. You may not find the real
world situation. The real world situation will be, when it comes to your
mind that you can use it, because you knew it existed.

It's been on some occasions that I have not seen a usage of feature that I
came across in a real world situation. However, I have been is some *real
world* situation that I knew that I could now implement that something that
I never saw a real usage for it.

It is what it is.

Sorry man, I can't find that golden goose for you.