This method is provides the Developer with a simple means of controlling data flow between client and server without fully implementing their own MarkupImageDataProvider. This method can be overridden in a derivation of either of the 2 provided MarkupImageDataProvider implementations (File and Sql) to retain all of the functionality of that MarkupImageDataProvider while giving the Developer the opportunity to intercept, reject, process, and alter the Markup Layer returned by any request.

If markupLayer is set to null or this method throws an exception, no Markup Layer will be returned to the client.

'Declaration
 
Public Overridable Sub OnRead( _
   ByRef markupLayer As ImGearARTDocumentXML, _
   ByVal documentIdentifier As String, _
   ByVal markupLayerRecordId As String, _
   ByVal documentContextData As NameValueCollection _
) 

'Usage
 
Dim instance As MarkupArtMiddleware
Dim markupLayer As ImGearARTDocumentXML
Dim documentIdentifier As String
Dim markupLayerRecordId As String
Dim documentContextData As NameValueCollection
 
instance.OnRead(markupLayer, documentIdentifier, markupLayerRecordId, documentContextData)

public virtual void OnRead( 
   ref ImGearARTDocumentXML markupLayer,
   string documentIdentifier,
   string markupLayerRecordId,
   NameValueCollection documentContextData
)

public: virtual void OnRead( 
   ref ImGearARTDocumentXML* markupLayer,
   string* documentIdentifier,
   string* markupLayerRecordId,
   NameValueCollection* documentContextData
) 

public:
virtual void OnRead( 
   ImGearARTDocumentXML^% markupLayer,
   String^ documentIdentifier,
   String^ markupLayerRecordId,
   NameValueCollection^ documentContextData
)