BackgroundWorker & Progressbar

Yes,
      I get your point. Actually there is varies type of connection so i can't limited it in a certain time period. So I think it's better to avoid progress bar because i build it for my those friends, who use slow connection, and waste lot of time to opening their mail ID to send mail.  :-)

Thank you sir.

How do you know how long it will take? Probably you don't know it will take longer than normal.
 
If so, then perhaps you can show a marquee style progress bar.
 
I assume you have a timeout value and your program will stop trying after the timeout period, so perhaps the progress bar could show the amount of time remaining before the timeout.
 
If you are unable to do the reading synchronously with a timeout that you can use to stop trying and then report progress then start trying again, then you must use asynchronous reads, and that will be a lot more work. It is something I have tried to do and I have not got it working entirely; I don't know what the problem is.
 

Actually sir i use this progress bar  to sending e-mail by c#,for faster speed connection, the mail will send very fast and progress bar will show the progress. But in slow connection like mobile-pc connection it take like 20-80 sec, during that time i want to show the user that "Don't give up hope, mail will send, although it take a long time."  :)
That's why I want to use progress bar.

I can use background worker & progress bar with "for" condition,
like for(int i=0;i<1000;i++).

But how i implement it, while it sending a mail?

help me plz!

Thank you Sir

Read the documentation and some of the many articles; this web site has articles that will help.
 
Do the work in the DoWork event. During the work, call ReportProgress and in the prgresschanged (whatever it is called) event update the progress bar.