Hello Amod,
Sorry for waiting, after confirm, this is not a bug, just some misunderstanding on this.
You should add InMemoryFeatureLayer to DynamicOverlay at the begining. Because the map won't be serialized using Ajax to call server method RaiseCallbackEvent. It means that the openlayers object won't be created again, you should just update the overlay intead of create one. Please see the attached sample.
If you want to add overlay dynamicly, you have to submit the form, which means the whole page will refresh, for example, there are 2 buttons(asp.net control) on the page, one named "button1", and the other one named "button2". This page implements ICallbackEventHandler, and when clicking button1, it will raise the server side method "RaiseCallbackEvent", which used to change Text value of button2, after that you can use JavaScript to get the Text value of button2, you will find out that the Text value of button2 isn't changed. And if this page doesn't implement ICallbackEventHandler, the whole page will refresh when clicking button1, and after that you can use JavaScript to get the new Text value of button2.
Please feel free to let us know if you have any queries.
Regards,
Gary
Issue7494.zip (249 KB)