Imar thank you for your complete answer
I don't want to insist on such abstract concept
but...(!!!)
I think when an ASP.NET application installed into a server and when users access it for each user there will be an instance of the webapplication but I don't know much about such instances for example
whether evry variable(gloabls or loacals like connection objects) is putted in this instance in the memory of user's machine, or only one unique variable would exist in IIS in the server
Imar supose my site have only one page(index.aspx)in this page I declare a connection as
a Global or Local connection and in my Page_Load, first I create the connection(by new method)then connect to database
and with a reader object I read lots of records from the connection and then I close my connection
now according to your answer you meant for global one the multi-tasking is not enabled
but for local one multi-tasking is enabled
you know in the above example when I don't need connection(Gloabl or Local)I close it(myConnectionObject.Close());then why multi-tasking can't work here
Imar excuse me because of my curiosity

I am not sure what exactly you mean by multi-tasking etc enabled in this context.

But anyway, if you create a connection in Page_Load, then each user requesting that page gets his or her own connection, because they are dealing with a page instance, which is a unique / separate object for each user.

However, if you define a static connection in the Global class or anywhere else, that connection applies to the entire application. The entire application in this context means really the entire application, not just the current user's request. So, with a global connection all users share that connection. With a connection in Page_Load all users get their own connection.

I think you're missing the point a bit about opening and closing a connection in your Global class. Sure, when you close the global connection, it becomes available for other users, but in sequential manner. User number 2 has to wait until user 1 is ready. When you define a local connection (as opposed to a global one), they can access the datastore simultaneously.

Cheers,

Imar
---------------------------------------
Imar Spaanjaars
Everyone is unique, except for me.
While typing this post, I was listening to: U.F.Orb by The Orb (Track 2 from the album: U.F.Orb) What's This?

I have gotten evry thing now
Therefore a static field(in the project's scope) is a unique field for all users
and all the multi-tasking and simultaneity and asynchronism about my connection object based on the above sentence.
Thank you very much.
Best Wishes.

I'd like to throw in a thought here if it hasn't been covered already.

It has been stated that "when I don't need connection(Gloabl or Local)I close it(myConnectionObject.Close())". What happens when one page process closes the global connection object while another page process is still using it? This isn't such a good idea.

Interesting thought. Hadn't even thought about that. That would quickly get you in major troubles as well.

Imar
---------------------------------------
Imar Spaanjaars
Everyone is unique, except for me.
While typing this post, I was listening to: Untitled by Eels (Track 15 from the album: Daisies Of The Galaxy) What's This?

Thanks to planio for his attention
when I were writing that thread ("when I don't need connection(Gloabl or Local)I close it(myConnectionObject.Close())" I didn't know exactly my Global connection is unique in all of my application....
but because of Imar's help I have understanded now....
Therefore you are righrt ,when a global connection closes for a user maybe(surely) for another user using it causes some problem(but I didn't know it about three hours ago)
did you know this site we discussed about only had one user(myself)
no problem!!!!:D:D
With lots of thanks

if you don't want to make an instance of the class everywhere do this.

namespace myProject
{
  public class Globals
  {
    public static string connectionString = "Bla bla bla, your ConnectionString here";
  }
}

You can acces this variable form another class like this.

Globals.connectionString;

If you don't want to make a new instance everytime this is one way you can access the variable from other forms.

melvik,

1) Create a class where your ConnectionString variable can be set and get as mentioned

2) If you want to use this class as a 'global' class, so that your application 'sees' this class in the same state, then, 'pass' this class around using setter/getter method...


ex.

//Inside the Startup, for example, it will initialize the XClass once.
XClass xClass = new XClass();


// set and get whatever you need
xClass.ConnStr = "bla bla bla";

// before calling the form1, 'pass' on the class
form1.XClass = xClass
form1.Show


Inside a form1:
XClass xClass = null;

public XClass XClass
{
    get {xClass;}
    set {xClass = value;}
}


I hope this helps.