My confusions are about which component will call ValidateUser method?
It is called by the Login Control
present in the page C:\Program
Do I need to call ValidateUser by myself (my application code), or depends on my needs (not always needed, depends on my application scenario);
IF you want to Authenticate the user to SharePoint then ValidateUser has to be called/will be called.
Is ValidateUser is called by SharePoint code (not my own application code), if yes, when (i.e. in what situations will SharePoint calls ValidateUser method, or say in other words, what operation in SharePoint will trigger invocation of this method)?
To be exact SharePoint does not do
authentication by itself it depends on
the provider/ By default it is
configured to validate the user based
on the Active Directory Windows
authentication. Where as you can also
configure it to validate aganist
different store ( FBA as you have
Being said that ValidateUser method is
automatically called by Login Control
when you click on the Sign In
button.Once the user has been
validated it drops a cookie so that
the further request form the browser
goes to the Server as the
[Update : To answer your comment]My question is, if I customize SharePoint login page and not using ASP.Net Login control, and for anonymous user, if the anonymous user access specific content which is blocked for anonymous users, will ValidateUser be called automatically?
No, Only Case when the ValidateUser
will be called is when you have a
ASP.NET Login Control and when you
click sign in button in it. Login
control is nothing but a Custom
Control that has Two TextBox, one
Button and a Check Box, and if you
don't want to use the default login
control then you will have to somehow
take the user name and password from
the user and use the Validate method
to authenticate him/her.
And to answer your second point ,
if you try to access a item that is
blocked for anonymous user then
SharePoint will contact the provide to
authenticate the user (Provider will
provide you the Login Screen) to put
it simple you will be redirected Login
On a Side note : Do not attempt to customize the Login.aspx present it the Layouts folder, because it is not recommended to do any changes to the SharePoint files.