SharePoint University

Hello Everybody,

I am creating a custom field type for Sharepoint List. While adding my custom fieid to a sharepoint list, i want to check for a condition and allow adding the field only if the condition is met. If the condition returns false I want to prompt the user an error message in the Field Settings page itself and restrict adding field.
I have tried to code this in overridden methods  OnAdded() and Update(). But its not working. I am new to Sharepoint and I dont know much about the inner working of Sharepoint.
Please give me some idea to slove this problem.


Arun Dutt

Arun,

In order to check when columns are added to a list you will need to make use of event recievers. These are custom classes derived from SPItemEventReceiver, SPListEventReceiver or SPWebEventReceiver. Just about all of these have to be registered programattically inside of SharePoint. I believe the SPItemEventReceiver can be registered via a Feature. I would spend a lot of time investigating these classes.

Hope this helps!

I would also check out http://blogs.digineer.com/blogs/gregm/archive/2007/06/27/sharepoint-event-handlers-part-1.aspx and http://blogs.msdn.com/brianwilson/archive/tags/Event+Handlers/default.aspx.

Hi Greg,

Thank you for the reply. I just visited the links you have given and it is really helpful for me

Arun  

 Hi westdccs,

Thank you for the reply. I think these event receivers can do my job. 

Arun 

 Hi westdccs,

 I have solved the problem. Thanks for your help. The following code worked for me.

    public override void FieldAdding(SPListEventProperties properties)
        {              
               // my logic here...
          
        }

Thanks & Regards,

Arun