SharePoint 2010 - Lists and Event Handlers

SPItemEventProperties

You can cancel the operation by using the Cancel property.

You can report an error message using the ErrorMessage property.

Cancel for Delete

You can cancel an item delete by setting the properties.Cancel = true:

public override void ItemDeleting(SPItemEventProperties properties)
{
properties.ErrorMessage = "Deleting Item is not permitted!";
properties.Cancel = true;
}

Try deleting an item from the Contacts inside SharePoint:

You will get the following message prompted:

Deploying the Event Receiver

You can use a note that, while you stop Visual Studio, the item deletion is allowed inside SharePoint. To make the event receiver permanent, use the project Deploy option.

Now try deleting an item without Visual Studio Debugging. You will get the same Error Message Dialog and this concludes the Event Creation and Deployment to a SharePoint site.

Properties of Project

You can change the URL and other properties created through the Wizard. Use "Project" > "Properties" to access/modify these properties.

Features

The event receiver is actually deployed as a feature inside SharePoint. You can view the Feature properties and the associated XML file under the Features special folder as in the following.



The Event code and Elements.xml reside inside the EvntReceiver1 group as in the following.

References

http://msdn.microsoft.com/en-us/library/bb736146%28v=office.12%29.aspx

Summary

In this article we explored the List Event facility of SharePoint. In advanced List Management these flexibilities are a great tool for a SharePoint Developer.