|
I'm about to write a C# application to, er, do stuff (not important). I'm going to provide request handlers that can take input from database tables, MSMQ and JMS queues (thank god for J#), Web service requests, HTTP requests, and maybe socket connections using a simple proprietary protocol or even a drop directory. Its admin interface will be ASP.NET pages.
I know pretty well how to write the logic in a nice way to satisfy all the requests from different input. My main question right now is how to arrange the components. I think I'm going to write the main body of the application as a Windows service, which'll give the benefits of startup, shutdown and even power-management hooks, as well as easy administration. I obviously need IIS for the Web services and HTTP support, which is great because it allows me to delegate security responsibilities for that stuff to IIS and the Web applications, as well as the opportunity to spread the load.
I figure the best thing to do is use a TCP/IP remoting channel with a binary formatter between the IIS applications and the Windows service, yes? (I've done some reading and practicing with remoting, but never used it in the real world.) Once I've done this, should I think about just making remoting another method of direct input into the Windows service? I mean, how valuable is it in general to provide access to something via remoting? I mostly see mention of it as a way to provide internal communication between components.
-Jeff
here, bloggy bloggy
|
|
|
|
|
Using .NET Remoting to talk to a Windows Service is very common, and the whole concept of communication between some server object (in this case, an ASP.NET Web Service) is not uncommon at all. Before (and still) server objects talk to COM+ services, which provide a lot of nice features for (almost) free.
As far as how ASP.NET talks to the back end, if you're not sure about Remoting perhaps consider using a provider pattern to make abstract calls to implementations: one could talk to .NET Remoting while another talks to another Web Service or directly to a database...whatever. Every since .NET 1.0 beta days when I realized how great the CTS was, I've been using a provider pattern for most of my bigger apps (including the solution I've architected here - though in a rush-to-market start-up I didn't have as much time as I needed, but will someday get around to revamping). Much of the .NET Framework already uses a provider pattern (.NET Remoting channels and sinks, System.Net authentication modules, etc., and ASP.NET stuff), and 2.0 will use it even more heavily (with great improvements).
Microsoft MVP, Visual C#
My Articles
|
|
|
|
|
provider pattern
That's a good name for it. That's what I'm used to doing, now. I create an interface for something that takes input, then make one implementation for every type. I do the same for the methods of output. Then, for things that need a synchronous response that depends on processing, I give the ability to associate a particular input method to a particular output method ("sink"). Each request carries context information, etc. Next I write the threading code, so that one thread is attached to each method of input. These threads read in requests (sometimes assigning them priorities; sometimes that's down the processing chain).
Each request is dropped into an in-memory queue at this point, and winds up getting processed eventually. Any sensed admin requests are sent to the front of the queue. Sometimes I make the same thread that processes the request write the output, but when performance is important I usually dedicate a separate thread to each sink too, especially if the same response or result has to be written to more than one output.
Since you bring it up, I have to say that the word "sink" to refer to output is awesome. I formed most of my personal naming preferences doing Java work, where everything in the API is "reader" and "writer" organized, with an occasional "sink" in there usually as the contribution of an old C coder! The word "sink" is now one of my favorite things about .NET. I really am a naming freak.
So you're saying that I could make the ASP app front end another method of input besides remoting, an interesting suggestion. Whatever I do with this thing, though, I'm going to have to provide synchronous responses for both the ASP and Web service requests, so I'm concerned about performance; like, I wouldn't want to funnel HTTP requests through the Web service.
I'll just have to try wading into the remoting stuff, I guess. I have zippo experience with COM+, although I've done some reading on it. I'm sure I'll have plenty of annoying questions in a week or so. 
-Jeff
here, bloggy bloggy
|
|
|
|
|
Each request to the Web Service (and .NET Remoting objects when hosted in IIS) get their own HttpContext, which runs in a separate thread of execution. While you may call a method synchronously in your client application, the web application uses a free-threaded model to execute it.
Microsoft MVP, Visual C#
My Articles
|
|
|
|
|
Mmhmm, that's good to know from a performance standpoint. So what you're saying, I think, is that Web services aren't plain awful on performance from a threading perspective, which I'm prepared to believe. I'm mostly worried about making the application consume too much of the available network resources, and I also figure that the encoding/decoding overhead of a binary formatter is going to be less than that of XML serialization and deserialization.
I was thinking a while back about writing a lightweight Web services provider that could be used outside of IIS, just to provide an easy point of entry into things like Windows services. I wouldn't be able to easily (read as ever) provide all of the built-in security functionality of Microsoft's Web services implementation, but I could make it easy to cobble together communication between your components in a snap. I don't know, maybe I'm overafraid of this remoting stuff. It seems pretty similar to Java RMI, which wasn't all that complicated.
-Jeff
here, bloggy bloggy
|
|
|
|
|
It's okay to be afraid of Remoting at first, but once you get the hang of it it's great! There you can use a BinaryFormatter which does improve performance (even just serializing/deserializing, not to mention the bandwidth required).
Microsoft MVP, Visual C#
My Articles
|
|
|
|
|
I've created a custom button and placed it in the designer toolbox. When I make changes to the button dll and rebuild it, I can then place the new button, with all the new features, on my form. The problem is that none of the previously-created buttons have the new features. Is there a way to tell the designer to use the new dll instead of the old one?
|
|
|
|
|
The designer has little to do with it. All the code is serialized to your code file (your .cs source file) and an assembly reference is added to your project references. In real-world solutions, you common add multiple projects to a solution and use project references - not assembly references (right-click on project, select Add Reference, then click the Projects tab). This keeps the version numbers in sync, as well as the makes the build configurations the same.
As far as the toolbox goes, putting controls you're currently developing in there is a big mistake since they change often.
Also, if you're working on a multi-project solution, I highly recommend NOT using automatic versioning (i.e., using an asterisk - * - in the AssemblyVersionAttribute common found in AssemblyInfo.cs). This can get to be a big pain really fast, especially when not all your assemblies are bound to each other (like a plug-in type application).
If you're building UserControl derivatives in the same project in which you're working, the designer usually (it's supposed to) adds them to the toolbox for the active project automatically.
Microsoft MVP, Visual C#
My Articles
|
|
|
|
|
Heath,
Thanks for your reply.
The control dll and the application are separate projects in the same solution. I set the version of both assemblies to 1.0.5000.0 (no auto-increment). The dll is added to the application as a reference project, just as you suggest. But still the old buttons are not updated when I rebuild the dll - not even if I remove and re-add the reference.
|
|
|
|
|
You also need to close and re-open the form or whatever container (like a UserControl). Also, the new assemblies aren't copied into the target directory until you build the project with the dependencies on the other.
Microsoft MVP, Visual C#
My Articles
|
|
|
|
|
Hi!.
There's a way to write an application such as Visual C++ SDI app., with multiple views, (forms views)?.
For example: I have two bars and selecting differents options, (buttons), I want to change the visualization, (the controls are others), in a kind of view or window in the center.
I use to do that with SDI application in VC++, but how could I do the same in C#.
Thank you.
Demian.
|
|
|
|
|
|
Is there any way to get processor related data from C#? I know there is Win API procedure but it, as far as I know, gives me specification related data (type, speed, etc).
I need something, to be specific => that will tell me % of processor ocupancy so I can for example when processor ocupancy drops below 10% to take some action.
Any ideas?
|
|
|
|
|
I've never done it, but one way you can do this is using the PerformanceCounter class. Read the docs-- it's pretty easy to understand how to go about it.
-Jeff
here, bloggy bloggy
|
|
|
|
|
|
Check out the class and all the other classes from Mentalis.org. I've used the this one before. It works pretty good.
CpuUsage[^]
The CpuTime class is a class that can query the current CPU load. This is sometimes useful to dynamically adjust performance settings in server applications.
This class is available in C# and VB.NET; it can be compiled to .NET modules or libraries to be used in other .NET languages. Since it relies on the Windows API, it will not work under Linux or FreeBSD.
I'm using it on a webform too.
webform[^]
|
|
|
|
|
Hi, I'd like to know how to use a Windows device driver (ex. parport.sys) in C#. I've been looking everywhere on the net but I haven't found any information about it!
|
|
|
|
|
Files like parport.sys have no exported functions, so you can't P/Invoke them. You need to either use the drivers through the HAL (or whatever is appropriate, like using the Windows Image Aacquisition (WIA) APIs.
Another option is to use Managed C++ and wrap the functionality in a managed class that you can use in your C# code.
Microsoft MVP, Visual C#
My Articles
|
|
|
|
|
I want to change the enter key action to do what the tab
key does (to change what was EnterAction property)
|
|
|
|
|
Handle the KeyDown event and use SendKeys.Send("{TAB}") as one example. If the text is currently being edited, then the TextBox hosted in that cell has the focus, so you should also also hook the KeyDown event of the DataGridTextBoxColumn.TextBox property and handle that in a similar fashion if this is the behavior you want while editing.
Microsoft MVP, Visual C#
My Articles
|
|
|
|
|
Hi,
I'm using Xml in c#. I want to use XSLT to sort the xml-file. This code is used when clicking on a button.
XslTransform trans = new XslTransform();<br />
trans.Load(@"c:\XSL.xsl");<br />
trans.Transform(fileName,destinationPath);
When i run this code the compiler stops right after this line:
trans.Load(@"c:\XSL.xsl");
He says there is a system error.
trans.Transform(fileName,destinationPath);
In this line he says something about "Obsolete" and "you should pass xmlresolver to transform() method"
Anybody an idea?
thanx a lot
|
|
|
|
|
In .NET 1.1, a lot of the methods on XslTransform are obsolete - meaning they will go away in a future version. You should not use them. Of course, if you intend to support .NET 1.0 you don't have a choice. Reading the documentation will help you determine what's obsolete, what's new, and how to use the classes instead of just using IntelliSense and guessing.
This is only a warning, though. If you're getting an error that either stops the code from compiling or that is getting thrown at runtime, then that's a different problem and you should post the exact exception that's being thrown.
Microsoft MVP, Visual C#
My Articles
|
|
|
|
|
The exact exception is weird.
He says:
An unhandled exception of type 'System.Xml.XmlException' occurred in system.xml.dll<br />
Additional information: System error.
He always stops at the line after this code:
trans.Load(@"c:\XSL.xslt");
no mather what i write so the problem is something with that line but it looks allright to me.
If this doesn't work, maybe you know a different way to sort my xml?
Thx a lot
|
|
|
|
|
It's likely that either your XSLT document is not well-formed XML or that you haven't specified the XSLT namespace (http://www.w3.org/1999/XSL/Transform).
Also, this is definitely the easier way. The only other way would be to navigate the DOM and either sort the data yourself or use an XPath navigator and wrote-out the DOM again in a sorted manner. XSLT does this for you.
It does work, but you're doing something wrong. The two problems I mentioned above are most likely the problems.
If you open your XSLT document in Internet Explorer, it should tell you where the error is if the document is not well formed (this is pretty simple to do programmatically too, but using IE you don't have to write anything). If the XSLT namespace isn't included, then your document is technically NOT and XSLT.
Microsoft MVP, Visual C#
My Articles
|
|
|
|
|
thanx! the namespace was the mistake, but it's an url so does the computer need an internetconnection for it to work?
I searched for this a looooong time, thanx a lot. But there are probably still some mistake in my xslt. He writes a new xml file which is good but he doesn't write the attributes so <library name="t"> becomes <library> and he doesn't sort the xml 
so i'll still be busy for while 
thx again
|
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
