How do I create button in c#asp.net in which it create auto increment number and flag is running along with that

The structure of your question implies that there are multiple processes in play at teh same time, but it's not at all obvious how these processes are distributed - or even what they are doing^*
So it's pretty much impossible to give you a definitive answer, except to say: "probably, don't".
It's generally a bad idea to "pre-assign" sequential numbers - and always a bad idea in a multi-user environment, which "ASP.NET" implies - instead, assign a temporary ID value (A GUID is a good choice) while you are processing, and only assign a sequence number when all processing is complete and final storage is being done. Any other approach gives problems such as multiple users trying to store under the same number, and "gaps" when the processing fails for whatever reason.

If you genuinely need this, you will need to explain in much better detail the structure of your whole app that relates to this requirement or there isn;t much we can do to help! Remember that we can't see your screen, access your HDD, or read your mind - we only get exactly what you type to work with.


* In future, it's a good idea to invest in punctuation, and also correct sentence case to improve the readability of your question - you have a keyboard full of characters so not using them makes you look like a child.