I've got a single Silverlight app that I'd like to display in a grid. The way the Silverlight app displays its content is dependent on the unique ID of the record in each grid row. Unfortunately, the XAP file is re-downloaded for each row in the grid. With a size of 700KB, this really impacts performance. Is it possible to download the XAP file once and then just re-use it for each row in the grid?
Once a XAP is downloaded Silverlight will cache the assemblies etc locally per instance of a Silverlight control. If you create another instance of a Silverlight control then this in turn has it's own domain that it in turn looks after.
My suggestion is to abstract out the parts you requrie and bake them into a seperate xaml, then load them into areas where you need them the most. If you still require a central .xap to handle the marshalling / event management etc then in Silverlight 3 we've put in place a Local Connection API which allows other Silverlight instances to talk to one another within the one browser page locally (ie SilverlighA can talk to SilverlightB all within index.html)
This can then allow you to establish a sort of local proxy if you will.
Scott Barnes / Rich Platforms Product Manager / Microsoft.