ASP. NET prevents users from skipping the login interface

1. Check that the logon is successful on the login page.CodeAdd the following code
Session ["userid"] = txtuserid. Text. Trim ();
Or
Session ["userid"] = "OK ";
For example, in the response event of my login. aspx. CS login button, the Code is as follows:
If (baseclass. checkuser (txtuserid. Text. Trim (), txtpwd. Text. Trim ()))
{
Session ["userid"] = txtuserid. Text. Trim ();
Response. Redirect ("Main. aspx ");
}
Else
{
Response. Write ("<SCRIPT> alert ('user name or password error'); location = 'login. aspx '</SCRIPT> ");
}
2. Add the following code at the beginning of page_load on each page:
If (session ["userid"] = NULL | session ["userid"]. tostring () = "")
{
Response. Write ("<script language = 'javascript '> window. Top. Location. href = 'login. aspx'; </SCRIPT> ");
}
For example, the page_load code in my main. aspx. CS contains the following content:
Protected void page_load (Object sender, eventargs E)
{
If (session ["userid"] = NULL | session ["userid"]. tostring () = "")
{
Response. Write ("<script language = 'javascript '> window. Top. Location. href = 'login. aspx'; </SCRIPT> ");
}
If (! Ispostback)
{
}
}
3. Try it ,,,