Context Bound Class, IMessage, Custom Attribute and Field problem

[Mark]

Hi,

Am trying to write custom validation attributes for public fields,
properties, methods etc. using context-bound programming.

It works fine for properties, methods, parameters etc.

But, when intercepting a Set of a public field, there appears to be an
underlying method set up; a FieldSetter, which take parameters type,
fieldname and fieldvalue.

The problem is that my Field's Custom Attributes don't seem to be
copied to the FieldSetter, so I can't determine what validation to
perform.

Can someone shed some light on this one? I'd really be most grateful


Mark.

 

[Alexander Shirshov]

Mark,

In a class which implements IContextProperty you should have a method:

public IMessageSink GetObjectSink(MarshalByRefObject o, IMessageSink next)

That's probably where you create an instance of IMessageSink implementor.
You could pass o (this is your actual context-bound object) to the
constructor and save it in a field:

public IMessageSink GetObjectSink (MarshalByRefObject o, IMessageSink next)
{
return new MySink(o, next);
}

class MySink
{
MyBusinessObject obj;

public MySink (MarshalByRefObject o, IMessageSink next)
{
obj = (MyBusinessObject)o;
}
}

Now it's a piece of cake to get the attributes:

public IMessage SyncProcessMessage (IMessage msg)
{
IMethodMessage call = msg as IMethodMessage;

if(call.MethodName == "FieldGetter"){
//Get the name of the field being accessed
string fldName = (string)call.GetArg(1);

FieldInfo fld = obj.GetType().GetField(fldName);
Attribute[] attrs = fld.GetAttributes();

...

The sample is a mess, but you should get the idea.

I also tried to implement the call interception framework...


HTH,
Alexander