Sometimes using viewstate and hidden form fields are just not enough to be able to control the actions and views of our website visitors. As an alternative we may wish to make use of cookies. Cookies are, typically, short peices of information stored on a users computer.
To handle cookies in .Net we need two functions, one for writing and one for reding our value:
Protected Function WriteCookie(ByVal CookieName As String, ByVal CookieValue As String)
Try
Dim objCookie As New System.Web.HttpCookie(CookieName, CookieValue)
objCookie.Expires = DateTime.Now.Add(New TimeSpan(0, 0, 30, 0))
Response.Cookies.Add(objCookie)
Catch exc As Exception
ProcessModuleLoadException(Me, exc)
End Try
End Function
Protected Function ReadCookie(ByVal CookieName As String)
Try
If Not Context.Request.Cookies(CookieName).Value Is Nothing Then
Return Context.Request.Cookies(CookieName).Value
Else
Return ""
End If
Catch exc As Exception
ProcessModuleLoadException(Me, exc)
End Try
End Function
To write a value to a cookie we will then call the WriteCookie function
WriteCookie("itemId", itemId.ToString)
And similarly to read the cookie value we will use theReadCookie function
If ReadCookie("itemId") = "" Then
Putting our read and write together we have:
Dim objc As New Controller
Dim obj As New Info
If ReadCookie("ItemId") = "" Then
itemId = objc.AddProperty(obj)
WriteCookie("itemId", ItemId.ToString)
Else
itemId = ReadCookie("ItemId")
End If
lblItemId.Text = itemId
In the above example I AddProperty is a stored procedure to add a property to a database, We first check to see whether the cookie has been set. If it has then we shall be using that value instead. If all is clear then we are free to add our property to the databse. This arrangement was used to prevent multiple inserts into a database, following repeated pressing of the browser refresh key.Sometimes using viewstate and hidden form fields are just not enough to be able to control the actions and views of our website visitors. As an alternative we may wish tou make use of cookies. Cookies
To handle cookies in .Net we need two functions, one for writing and one for reding our value:
Protected Function WriteCookie(ByVal CookieName As String, ByVal CookieValue As String)
Try
Dim objCookie As New System.Web.HttpCookie(CookieName, CookieValue)
objCookie.Expires = DateTime.Now.Add(New TimeSpan(0, 0, 30, 0))
Response.Cookies.Add(objCookie)
Catch exc As Exception
ProcessModuleLoadException(Me, exc)
End Try
End Function
Protected Function ReadCookie(ByVal CookieName As String)
Try
If Not Context.Request.Cookies(CookieName).Value Is Nothing Then
Return Context.Request.Cookies(CookieName).Value
Else
Return ""
End If
Catch exc As Exception
ProcessModuleLoadException(Me, exc)
End Try
End Function
To write a value to a cookie we will then call the WriteCookie function
WriteCookie("itemId", itemId.ToString)
And similarly to read the cookie value we will use theReadCookie function
If ReadCookie("itemId") = "" Then
Putting our read and write together we have:
Dim objc As New Controller
Dim obj As New Info
If ReadCookie("ItemId") = "" Then
itemId = objc.AddProperty(obj)
WriteCookie("itemId", ItemId.ToString)
Else
itemId = ReadCookie("ItemId")
End If
lblItemId.Text = itemId
In the above example AddProperty is a stored procedure to add a property to a database, We first check to see whether the cookie has been set. If it has then we shall be using that value instead, inhibiting the creation of a new row in the database. If the cookie has no value we are free to add our property to the database. This arrangement was used to prevent multiple inserts into a database, following repeated pressing of the browser refresh key.
NAT February 2006