Dilemma

As this page of the Apex docs indicates, you can’t just make a User trigger that updates a Contact or an Account, because it’s forbidden to modify those “non-setup” objects from a “setup” object like User.

Solution

Fortunately there is a simple solution: the @future annotation.  The @future annotation allows you to create Apex that runs asynchronously at some point in the future (in my tests I’ve found that it runs immediately, or at least very soon after the trigger executes).  Methods that use @future are subject to different limits than normal trigger operations because @future methods don’t hold up the trigger (and therefore the entire user experience) while they’re working.  Therefore @future methods are often used to perform long-running web service callouts from triggers asynchronously.  However, they can also be handy for a case like ours, where we want to update an object that we’re not normally eligible to update.

Calling a method that has been marked as @future is just like calling any other static method.  Here’s my trigger, short and sweet:

trigger UpdateContactFromPortalUser on User (after update) {
	//We only want to run on the single item that the user edited
	if (Trigger.new.size()==1) {
		User u =  Trigger.new[0];
		//And only if it's a portal user
		if (u.ContactId!=null) {
		UpdateContactFromPortalUser.updateContacts(u.Id);
		}
	}
}

Let’s see how that works.  In the example given here, I just update a couple of fields from the user record: the name, the email address, and the title.

global class UpdateContactFromPortalUser {
    @future
    public static void updateContacts(String userId) {
    	User u = [select ContactId,Email,FirstName,LastName,Title
    				from User
    				where Id=:userId];

    	if (u!=null && u.ContactId!=null) {
	    	Contact c = new Contact(Id=u.ContactId);

			c.Email = u.Email;
			c.FirstName=u.FirstName;
			c.LastName=u.LastName;
			c.Title=u.Title;
			update c;
		}

Source :  http://blogs.salesforce.com/support/2009/01/index.html

Scenario :
We are building a Visualforce page for creating a case. Now there are fields in case which are read only for all profiles except System Adminstrator. I need the user to enter the value for this field and so I created my page with a controller and not a standard controller. Also in my controller we have added the modifier as without sharing.

Now when we log in through another user, we still see the field as read only on the page. However from the controller we are able to insert value or update the field. It seems to me that the page is running in User mode following the user profile permissions and field level security while the controller is running in Sytem mode. Is this the intended behaviour or are we missing something

Following are few of the possible solutions….

Solution 1

It is an intented behaviour, If the fields rendered on the page is strongly binded (i.e Value = {!ObjectName.Fieldname}).
Why not create input/HTML fields and bind them using getter setter method (i.e you take input in a normal text field and bind it to the actual field in the controller). As these input Html fields are not binded to an object these fields will be editable regardless of profiles.

Solution 2

Create a Custom Object and assign permissions to this object to all profiles. Now render fields of that custom object, but in your controller don’t insert this custom object. Insert the actual records.
Use this custom object to generate the lookups and date pickers
The controller will be standard controller of this custom object with extensions.
So this object is used just to render fields ….

Solution 3

Make the fields read only at the page layout level and not at the profile level.

I look through the documentation and didn’t see a system method that converts a date time field to a date. There is one for formula fields but is there one for Apex?

Solution : Just create a date newInstance() and pass in just the year,month,day from the dateTime object.

Datetime dateTimetemp = System.now();

Date dateTemp = Date.newInstance(dateTimetemp.year(),dateTimetemp.month(),dateTimetemp.day());