how to save login & logout time in database using asp.net

Yes it is so simple when u login update tabel logincolumn as well as logout...
for it you will have to get system value and can do it....

refer this link

http://www.asp.net/security/tutorials/an-overview-of-forms-authentication-vb[^]

CREATE TABLE USERLOG(
   ID INT IDENTITY(1,1) PRIMARY KEY NOT NULL,
   USERID INT,
   LOGIN DATETIME,
   LOGOUT DATETIME
)

CREATE PROCEDURE SP_TRACK_USERLOG
	@USERID INT = NULL,
	@COMMAND INT = 0
AS
BEGIN
	SET NOCOUNT ON;
	IF(@COMMAND = 0)
		BEGIN
			INSERT INTO USERLOG (USERID,LOGIN,LOGOUT) VALUES (@USERID,GETDATE(),NULL)
		END
	ELSE IF (@COMMAND = 1)
		BEGIN
			UPDATE USERLOG SET LOGOUT = GETDATE() WHERE USERID = @USERID
		END
END

SqlConnection cs = new SqlConnection("YOUR CONNECTION STRING");
cs.Open();
SqlCommand cmd = new SqlCommand();
public void Login(int userID)
{            
   cmd.Connection = cs;
   cmd.CommandType = CommandType.StoredProcedure;
   cmd.CommandText = "SP_TRACK_USERLOG";
   cmd.Parameters.AddWithValue("@USERID", userID);
   cmd.Parameters.AddWithValue("@COMMAND", 0);
   cmd.ExecuteNonQuery();
}
public void LogOut(int userID)
{
   cmd.Connection = cs;
   cmd.CommandType = CommandType.StoredProcedure;
   cmd.CommandText = "SP_TRACK_USERLOG";
   cmd.Parameters.AddWithValue("@USERID", userID);
   cmd.Parameters.AddWithValue("@COMMAND", 1);
   cmd.ExecuteNonQuery();
}

Hi,

use session_start and session_end events.

In Session_start event write code for login in DB table
In session_end event write code for logout in DB Table

Try yourself some code If there are any error post your question with code

All the Best

Take the value of System.DateTime.Now after successful login & logout events and store it into database.
Do you need anything else to be done?