Check session null empty c#

First is new session created when new visitor comes to website. Second type is session which is created because previous session expired. If visitor is not made any request longer than specified in Session. TimeOut property 20 minutes by default , session will expire.

But, IsNewSession property can't distinct these two cases. The same worth for checking value of some session variable. You can try to place some value in session variable and check it later to see if variable is empty.

Something like this:. As you see, like IsNewSession property, this code can't say is it new visitor with fresh session, or existing visitor with expired session. It can tell us only if session collection is already existing, but can't say is it expired or not. We'll define expired session as situation when Session. IsNewSession is true it is a new session , but session cookie already exists on visitor's computer from previous session.

Here is a procedure that returns true if session is expired and returns false if not. Headers[ "Cookie" ]; if null! IndexOf "ASP. You can place this function on page if you need it in single file. Another option is to create base page class with this function included, and then inherit all pages from that base page.

Sometimes this could be complex if you have existing website with large number of pages. One more option is to use master page. If IsSessionExpired function returns true, you can do appropriate action, like show a message in label control which informs user that session is expired, redirect user to some SessionExpired.

So we don't need to check IsNewSession value like in previous example. Here, we need only second condition i. Also, it is a lot of faster and easier to write this short code to Global. If your website has a lot of pages, and you don't use master page already, it could be huge task to relate master page to each. In the other hand, if you need to check if session is expired only on few pages, not in complete website, then is justified to use master page or even create base page.

This event theoretically fires when session expires. Current inside of this procedure. That means that you can't redirect visitor to Your-Session-Is-Expired.

That narrows options and possible uses of this method. More about different session state modes you can read in ASP. In previous examples, session expiration check comes when visitor makes new request. Copy Code. Add your solution here. OK Paste as. Treat my content as plain text, not as HTML. Existing Members Sign in to your account. This email is in use. Do you need your password? Submit your solution! When answering a question please: Read the question carefully. Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.

If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome. Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question. Let's work to help developers, not make them feel stupid. ColumnName, row[col] ; rows. Wednesday, December 3, AM. Wednesday, December 3, PM. User posted Hi xandeq, Thanks for your post.

For this purpose you can make a custom attribute as shown :- Here is the Class which overrides ActionFilterAttribute. Best regards, Eileen. Thursday, December 4, AM. User posted Before assigning the Session value to the Id first checkfor Null exception by putting in a try catch block.

Sobefore assigning, if Session["Id"]! Any ideas?