I am transfering the head of a hierarchy of objects to the client for them to choose which one they want to see details for. The list returned in this initial fetch is bound to a datagrid control, and some of the data items are displayed in the grid. The rest of the data is loaded lazily through a destination via the java assembler. Once a request for the rest of the object is received I do return quite a lot of data and it can take up to 2 seconds for the response to arrive back at the client.
One immediate question is how I show a progress bar or a wait cursor while this operation is occurring. In all honesty I would prefer it was synchronous but I can't seem to force that to happen. So, I have a partially loaded object and when the remainder of the data does finally show up I recalculate some of the fields that I am displaying in the orginal data grid because they may be stale. What I have found is that I get a stack overflow where the data binding manager is busy watching changes to the members of the class that I am busy re-calculating. During recalculation I get an itemPending error which causes my recalc function to be re-called which touches the bound data items which causes the data binding manager to kick off again. And round and round we go until I either run out of stack space or the server stuff returns just in time and my data show up. I have tried to separate out the activities so there is no binding during loading, but this is causing me some horrible usability issues and seems to be a bad way of approaching the problem. What's more the asynchronous nature of the server interaction is such that I can't tell when exactly I'm going to receive the data (I have to rely on trapping itemPending errors) so I don;t really know when it is safe to re-bind. What I would like to be able to do is just suspend the data bindings in the client code while the lazy loading is taking place, and then re-bind when I know I have all the data. Any hints or architectural suggestions would be greatly appreciated. SP
