How to prevent document editing and properties updating

Question

I need to be able to prevent the document in document library to be edited and it's properties updated when the custom document property DocState has a value Reviewed. Should I use document library event handlers? If yes, how?

Pseudo code

SPListItem document;
document = this.Web.Lists["Document Library Title"].GetItemById(x);
...
if (document["DocState"].ToString() == "Reviewed")
{
  // preventDocumentContentEditing!
  // preventDocumentPropertiesUpdating!
}

Thanks!

Answer 1

You can use SPItemEventReceiver to create your own event receiver. In your receiver you can implement ItemUpdating method. In this method you can retrieve item from SPItemEventProperties. Compare item field value with your value and use following code to cancel update:

properties.Cancel = true;
properties.ErrorMessage = "you can not update this item";