离开一页时如何清除会话

Question

I googled this about 1/2 a hour no hit's. Scenario is that, dynamic scripts are saved in string builder whose "string" representation is stored in session. It just happens that when user navigates away from one page to another the script[from session] gets registered using "RegisterStartupScript" . The script is registered in PreRender event of the Page. So i would like to clear this script in session while the page navigates away btw rule out a option to create another session variable and clear previous one. It's a overhead :(

Answer 1

Why are you storing this in Session, do you need to maintain this script in between GET requests?

If only postbacks are relevant you could store it in viewstate as this is maintained only when doing a postback.

If you want this string to be available on GET requests too you might want to introduce a different variable which has an identifier identifying the page for which the script is generated. If the requested page doesn't match the control variable you will have to generate a new script.

Answer 2

您可以使用JavaScript onUnload()并调用AJAX服务，这将清除服务器端会话。

Answer 3

How is the user navigating away from the page? Can't you use an ASP.NET button instead of a hyperlink, and then do a Redirect in code once you have cleared your session variable?

protected void btnDoSomething_Click(object sender, EventArgs e)
{
    Session["Value"] = String.Empty;
    Response.Redirect(strURL, false);
}

OR You could add a variable in the query string and check it in the Page_Load event of the target page:

Webform1.aspx?reset=true

Answer 4

Since I cant comment yet, use onUnload().

It fires on full postbacks too. Ajax postbacks dont fire!

What you need to do, is guaranty inside the onUload function that you only clear the session when you want. Like setting a variable isPostBack to true before the postbacks so onUnload sees the variable and doenst send a request to clear the session.