It does this by creating a special crawled property that starts with ows_tax Id_ and then the name of the field, and a managed property that starts with owstax Id.For example if we have a field called Regional Office then we will end up with a crawled property named ows_tax_Id_Regional Office automatically mapped to owstax Id Regional Office (in addition to the crawled property ows_Regional Office that is not mapped to any managed properties).They are used to perform some custom action after an event occurs.These events are asynchronous because they need not happen immediately after the event is performed. SPWeb Event Receiver : This provides event handling whenever a site or a site collection is deleted or moved Each of the classes has some virtual methods which are to be over-ridden to perform our custom action. Methods under the class SPWeb Event Receiver handle site level events. Site Deleted – This occurs after a site collection is deleted.Field Adding – This occurs when is field is being added to a content type.Field Deleted – This occurs after a field is deleted from a list.Synchronous event receivers are also known as ‘Before’ event receivers.They are used to perform some custom action before an event occurs.
When you add or edit a document in the list or library the event receivers combine the values of all the taxonomy fields into the Tax Catch All Label column and the values of all the hidden note fields (i.e. To show how this works I’ve included an example of the values for a document that contains two managed metadata fields; a Regional Office field that contains the single value ‘New Zealand’, and a Brand field that contains the values ‘Coca-Cola’ and ‘Cadbury’.We have many Share Point event receiver classes in order to handle variety of events.There are basically two types of event receivers: Synchronous and Asynchronous event receivers.I’ve been working with the managed metadata functionality provided in Share Point 2010 fairly extensively over the past few months.While it is a great feature and works well when used through the UI it has several rough edges that can cause problems when you are deploying features that use managed metadata fields.