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Hello,
i want to communicate between a client/server application with HttpWebRequest an HttpWebResponse. My problem is, that i have a server farm. I want to have sessions and want to be able to send and receive informations.
The problem is now, that i can't really work like a web-Server. A request and i deliver a response. I need to talk on one connection in a duplex way. So is it possible to create a HttpWebRequest and to send informations in it, receive some informations and use the same Request(Connection) for sending another Informations?
Thank you
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Hello SoftwareJaeger,
The short answer is NO, HttpWebRequest/Response is just that a single request and response. You can constantly open, close and re-use them all you like but you are not going to get the bi-directional (or duplex) communication you are looking for.
What you need is to actually open TCP or UDP sockets and then send all your calls from there. Really a very basic example would be a chat client (i.e. Windows Live Messenger) which implements the type of functionality you want. There is a great little article here on CP that will walk you through creating a chat client with UDP sockets here[^] that will illustrate the principals of what it is that you need to do.
Don't comment your code - it was hard to write, it should be hard to read!
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A little back story to Adam's response:
HTTP is a stateless protocol. You fire, and you're not necessarily guaranteed a response. In some web farms sessions are maintained across servers, but in others, the sessions are load balanced. You should be able to rely on session data, but it is still not proper stateful communication.
The client makes a request (breaking it down, even, in multi-part scenarios).
The server fulfills the request (by returning a status code and possibly payload).
That is the end of com.
As Adam suggested, you'll need to drop to a different protocol/level to achieve what you're looking for and maintain the open connection.
Cheers.
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Hi,
I am working on an application which needs to monitor the system states (power states) and display modes.
I would like to know if there is a way to register my application for power states (s0 -s5) change events? I mean if the system power state transitions from s0 - s1 etc.
Also how would we know if the display mode is changed from lets say dual display, cloned display etc?
I am trying to get these information on net but in vain 
Any help is appreciated.
Regards,
HalliHaida
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Sadly I cannot give you an accurate answer. I really don't know but when I have to do something similar to what you are posting, I always have a look at WMI Classes. Maybe you will find something useful there.
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Hi,
some system-oriented events are available through the SystemEvents class; however I doubt you'll find exactly what you want there.
The alternative is by having a Form, overriding its WndProc, and looking for the right Windows messages, such as WM_POWERBROADCAST[^]. I don't know what message is sent when the dual monitor setup changes, I trust there is one though.
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Hi! I have this code:
class Program
{
static void Main(string[] args)
{
List<Bar1> bar1List = new List<Bar1>();
bar1List.Add(new Bar1());
bar1List.Add(new Bar1());
bar1List.Add(new Bar1());
List<Bar2> bar2List = new List<Bar2>();
bar2List.Add(new Bar2());
bar2List.Add(new Bar2());
bar2List.Add(new Bar2());
List<Foo> fooList = new List<Foo>();
}
}
abstract class Foo
{
public string type;
public Foo(string type)
{
this.type = type;
}
}
class Bar1 : Foo
{
public Bar1() : base("Bar1")
{
}
}
class Bar2 : Foo
{
public Bar2() : base("Bar2")
{
}
}
Notice lists "bar1List" and "bar2List". I would like to add all those elements of those lists into the "fooList".
I know I can use .ConvertAll<Foo>()-method from "bar1List" and "bar2List" with a appropriate delegate converter method, but I would like to know if there are any better solutions?
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List<Foo> bar1List = new List<Foo>();
bar1List.Add(new Bar1());
bar1List.Add(new Bar1());
bar1List.Add(new Bar1());
List<Foo> bar2List = new List<Foo>();
bar2List.Add(new Bar2());
bar2List.Add(new Bar2());
bar2List.Add(new Bar2());
List<Foo> fooList = new List<Foo>();
fooList.AddRange(bar1List);
fooList.AddRange(bar2List);
Real men don't use instructions. They are only the manufacturers opinion on how to put the thing together.
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Just what I needed! Thanks!
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You're welcome!
Real men don't use instructions. They are only the manufacturers opinion on how to put the thing together.
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Hi
I am trying to develop a program in which I have to scan an image and pick out some stuff from it.
Assume that I have the image (in jpg).
The image contains Multiple Choice Questions with answers (marked with a black dot next to it).
Now I need to read the image and calculate the total right answers.
I am planning to do this in C#.net.
I have read Christian Graus articles for image processing but didn't find them relevant to my program.
Can some help me about how i should begin?
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Message Closed
modified 23-Nov-14 5:52am.
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Yes, thats how i am trying. But its too much of labor!!
how can i detect a dot (for answer) or a number (for question number) in the image?
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This is a relatively complex task, even though it doesn't seem like it.
1st you need an algorithm to find the answers. If you can make the questions on the exam one per page or a fixed size you'll reduce the complexity, as would fixing the position of the answer grid. This helps with finding the answers in the scans by reducing the area they appear in. Another solution would be to print some solid bars on the side of the page and find those, they should be level with the answer. If the bars are skewed (e.g. the scan is skewed) you should be able to work out the rotation from there. If the bars are on the wrong side the scan is upside down which could happen. You can then straighten the image and re-find the answer
Once you know where the answer grid is A neural network would be easy to train for yes/no ABCDE type answers if you are so inclined(especially if the number of choices is fixed, the NNW takes the answer squares area pixels as input, and categorises to a number of outputs each representing and answer. That said, an algorithm might just be easier, say identifying the squares and finding which, in order has the most black pixels.
The first step will probably need the scan colour depth reduced to 1-bit to make, this makes processing the image easier, and requires less memory if processing lots of scans. You'll also need a
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OK Keith and OriginalGriff have given a huge idea. Thanks a lot guys.
I will start in that direction. I hope I get the right to modify the question paper. If thats possible, then the project seem feasible for a single person.
Also Erik, could you please explain what module you developed?
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Keith is correct, but there is another way which can make locating the answers easier, (if you have control of the paper). Put registration marks in two (or preferably four) of the corners. If you make these a specific colour so they are easy to find, than locate the marks and use them to find the answers since you know the relative positions.
Real men don't use instructions. They are only the manufacturers opinion on how to put the thing together.
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Just to confirm this answer, I did it this way some time ago for a format recognition module.
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Hello Experts,
My Application is writeen in C# (2.0 Framework) for windows Application. Now i want to built same application For Mac OS.
I am not familier with MAC OS.Is is Possible to convert myapplication to MAC OS with the Help of MONO.
Your suggetion and help required.
Please describe me the steps to built application for Mac.
Thanks
If you can think then I Can.
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See here: http://www.mono-project.com/Mono:OSX[^] I haven't tried it myself (but if it's anything like Mono on linux, expect annoying little problems, and test, test and test everything again).
Real men don't use instructions. They are only the manufacturers opinion on how to put the thing together.
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Thanks for Reply,
please describe me shortly how to work with that.
If you can think then I Can.
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eg_Anubhava wrote: please describe me shortly how to work with that.
Did you read where I said "I haven't tried it myself"?
You will have to read and learn... we can't spoon feed you everything!
Real men don't use instructions. They are only the manufacturers opinion on how to put the thing together.
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But my question is I have the knowledge of MONO. and I have generate the problem with using MONO.
I already describe in my question.
If you can think then I Can.
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- Download[^] Mono and install it.
- Compile your sourcecode:
mcs Program.cs
- If you're having trouble compiling from the console, and you'd want to compile from the Visual Studio IDE, consider buying the Mono Tools[^].
- Specific questions targetting Mono can be posted on the Mono Forum[^]
Enjoy
I are Troll 
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Thank you sir
If you can think then I Can.
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Hi, I would like to download images in the background from an URL. I currently had a program which is downloading an image from a URL. However the application i created will "freeze" until all the image had be downloaded.
Hence, I am looking for a way to download images from an URL in the background. So i would be able to continue to use the program while it download.
I am new to C# (WPF) and I am still learning. Hope you guys can give me some suggestion or links for references. Thank you
I tried the following links but error occurs.
http://msdn.microsoft.com/en-us/library/ms229675(v=VS.85).aspx
Download an image, it freeze my program:
http://msdn.microsoft.com/en-us/library/system.net.webclient.downloadfilecompleted.aspx
Thank you very much!
Janet
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