Event receiver CancelWithError

Question

I need to show an error message during in the ItemAdding event from a SP2013 event receiver.
I used this code in case of error:

properties.Status = SPEventReceiverStatus.CancelWithError;
properties.ErrorMessage = "My error";

I can see the error in the page but It shows also all the trace stack.
How can i show the more beauty sharepoint default error template. (with my error description)?

Answer 1

To see a more "beautyful" error, you could enable custom errors in web.config

<customErrors mode="On" />

(Help: http://social.technet.microsoft.com/wiki/contents/articles/6171.sharepoint-2010-modify-web-config-to-display-error-details.aspx)

and then use this code:

properties.ErrorMessage = "Error";
properties.Status = SPEventReceiverStatus.CancelWithError;

Answer 2

You should use CancelWithRedirectUrl. Then show the error message on that custom page.

properties.ErrorMessage = "Error";
properties.Status = SPEventReceiverStatus.CanceWithRedirectUrl;
properties.RedirectUrl = url; //Pass the error message in query string

Create a custom page and on Page_Load read the query string and show it in a label.

http://waelmohamed.wordpress.com/2013/06/10/create-custom-error-page-for-sharepoint-event-receiver/