Re: stateless design - C# Discussion Boards

23-Mar-08 21:54

Hello everyone,

I do not understand what means "A stateless design (popular for reasons of scalability) intrinsically limits the possibility of interaction, since classes are unable to persist data between each request." and why such design will be better to scale. Any more descriptions?

http://www.albahari.com/threading/part2.html

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Another way to cheat is to minimize thread interaction by minimizing shared data. This is an excellent approach and is used implicitly in "stateless" middle-tier application and web page servers. Since multiple client requests can arrive simultaneously, each request comes in on its own thread (by virtue of the ASP.NET, Web Services or Remoting architectures), and this means the methods they call must be thread-safe. A stateless design (popular for reasons of scalability) intrinsically limits the possibility of interaction, since classes are unable to persist data between each request. Thread interaction is then limited just to static fields one may choose to create – perhaps for the purposes of caching commonly used data in memory – and in providing infrastructure services such as authentication and auditing.
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thanks in advance,
George

N a v a n e e t h23-Mar-08 22:53

N a v a n e e t h

23-Mar-08 22:53

George_George wrote:
A stateless design (popular for reasons of scalability) intrinsically limits the possibility of interaction, since classes are unable to persist data between each request

Yes as told in the article, this is another way to minimize thread interaction. Webservers communicates with the clients through HTTP protocol. When a request arrives at the webserver, it processes and sends the response back. It's not persisting the data(HTTP is stateless) . Instances will be created and disposed before sending the response, also each request has it's own thread. This limits the interaction between threads. But static classes will be there in the memory for long time, so thread interaction is needed there.

Hope it's clear

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George_George23-Mar-08 22:58

23-Mar-08 22:58

Thanks N a v a n e e t h,

Your reply is clear. Question answered.

regards,
George

N a v a n e e t h23-Mar-08 23:15

N a v a n e e t h

23-Mar-08 23:15

Glad to know it helped Smile | :)

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led mike24-Mar-08 4:59

led mike

24-Mar-08 4:59

George_George wrote:
This is an excellent approach and is used implicitly in "stateless" middle-tier application and web page servers.

Not sure I believe that is completely accurate. There seems to be a mixing of several things into one and making a point that is not valid for all of them. HTTP is a stateless protocol. That has nothing to do with threading. And in fact modern Application Servers do provide mechanisms to manage state in an HTTP context. While the point about static data is accurate it's mixed in a discussion of Application Servers which don't use static data to provide state mechanisms.

Perhaps I am reading it wrong but I find that paragraph confusing and I'm not at all sure that it is accurate.

led mike

George_George24-Mar-08 18:53

24-Mar-08 18:53

Hi led mike,

Which point or points do you think is inaccurate? HTTP is stateless (almost), but still use minimal static data which needs to be synchronized by threads, I think this is both the points from my quoted article and your points.

regards,
George

led mike25-Mar-08 6:34

led mike

25-Mar-08 6:34

George_George wrote:
Which point or points do you think is inaccurate? HTTP is stateless (almost), but still use minimal static data which needs to be synchronized by threads

No, I thought I was very clear on that:

led mike wrote:
HTTP is a stateless protocol. That has nothing to do with threading.

led mike

George_George25-Mar-08 20:20

How to Copy Data from Data Grid view to another gridview

25-Mar-08 20:20

Thanks led mike,

Question answered.

regards,
George

Send Text

M Riaz Bashir23-Mar-08 21:48

M Riaz Bashir

23-Mar-08 21:48

Hi,

kindly tell me the solution or give the ready made samples of following:

The "notepad" is already loaded and I want to send "Hello Notepad" to "notepad" application.

Thank you in advance
(Riaz)

Re: Send Text

Giorgi Dalakishvili23-Mar-08 21:57

Giorgi Dalakishvili

23-Mar-08 21:57

Here is an example that sends text to calculator. You can easily modify it to work with notepad.
How to: Simulate Mouse and Keyboard Events in Code[^]

Giorgi Dalakishvili

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Krazy Programmer23-Mar-08 20:23

Krazy Programmer

23-Mar-08 20:23

Hi i am having two datagrid views in my form
User is entering data into the gridview 1
and i have provided a button ...
So how to copy the data from the first gridview to second on button click ...
Here i can implement a recursive method to do this ...want to know is there any other way to do this
Thank You

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Re: How to Copy Data from Data Grid view to another gridview

Christian Graus23-Mar-08 20:37

Christian Graus

23-Mar-08 20:37

Why would you need recursion when a gridview has only one level ?

Christian Graus - Microsoft MVP - C++

"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )

Re: How to Copy Data from Data Grid view to another gridview [modified]

Krazy Programmer23-Mar-08 20:44

Krazy Programmer

23-Mar-08 20:44

i mean to say a loop for assigning the grid view 1 cell data to grid view 2..

CG I have solved this ...i know i am starting another thread here sorry

One more question when user clicks on the column head cell contents get sorted how to restrict this ....

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modified on Monday, March 24, 2008 3:03 AM

Re: How to Copy Data from Data Grid view to another gridview

salon23-Mar-08 21:13

Re: How to Copy Data from Data Grid view to another gridview

23-Mar-08 21:13

Hey! the problem is solved, it needed a static class

Krazy Programmer23-Mar-08 21:19

Krazy Programmer

23-Mar-08 21:19

Sorry My Dear Friend

Try this Take a Grid View on the form with two columns In the load event add 10 rows to it
Restrict user from adding and deleting rows
now run the application

Example : S.No Phone_Number
1 23232
2 45324
5 23422

Now click on the S.No which is the Column header you will find that there positions are changing and getting sorted up.. I want to restrict this thing

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string enum in c#

salon23-Mar-08 20:01

23-Mar-08 20:01

Can we do like this in enums

enum myStringEnum {
enumItem1 = "value 1",
enumItem2 = "value 2",
etc
}

i.e.spaces in the string value, I know we can assign int value to enum
but I m not sure whether string values (with spaces) can be assigned to enums.
If no, then can we have some alternative?
Since I want the string values with spaces in enum Sniff | :^)

darkelv23-Mar-08 20:23

darkelv

23-Mar-08 20:23

Nope you can't. You can use underscore. Poke tongue | ;-P

You can put a Description attribute to the enum

public enum EnumTypes
{
[System.ComponentModel.Description("Nothing To See Here")]
Null = 0,
}

and use DescriptionAttribute to read the Description. But for datagridview, databinding etc, it will show the enum (not the description).

salon23-Mar-08 20:47

23-Mar-08 20:47

and if i want to use the value in description then how can i retrieve this,
I mean I have "value 1" i.e. string value (with spaces) in database and I want this value to the database value and retreive some records,
then m i able to get the string value?

darkelv23-Mar-08 21:19

darkelv

23-Mar-08 21:19

Nope, you can't directly.

Work around is (not recommended, it's messy)

1. From database, read "value 1"
2. Make a function to map "value 1" to the enum value base on the Description value, using loop, etc.
3. Use the enum in your code, etc.
4. When saving to database, save the enum's Description.

salon23-Mar-08 21:50