MapForums

Dear All
I have a problem with MapPoint in my vb.net application.

I use MapPoint to show my vehicles on map.

My application is a MultiThread application and when I try to show a GPS Position on Map while MapPoint is busy to build the route I have a 'server busy' error.

Are there any properties or events to know when the MapPoint Activex is in busy state?

I try to use the "ReadyStateChange" event but it doesn't occur during route building and other functions.

Thanks Matteo

Hi,

The 'server busy' shows up because your application does not resond to windows messages.

__________________
rgds, Wilfried Mestdagh
www.mestdagh.biz
MapPoint coding demo
Order MapPoint 2009 with Routing and User Tools Spreadsheet

Thanks Wilfried for answer

But are there any properties or event to know when MapPoint ActiveX Control is busy state to prevent this error message?

Thanks again
Matteo

Hi,

The 'server busy' popup is in fact a very confusing message. It does not mean mappoint is busy, it means that mappoint is trying to process windows messages to your application and your application does not respond. But that's not all. I try to explain when it can show up:

- Your application is not pumping messages on a (hidden) window. This can for example happen if it is looping somewhere during a long time. (I think >= 10 seconds). If that is the case then optimize the length operation or move it into a background thread.

- Your application is pumping messages, but has a modal form in one of the Mappoint events. For example a popup menu.

- If your application is multithreading and there is a hidden window created in one of the threads, be sure to have a working message pump in that thread. Note that this is not nececary if you have no window over there.

There could be more reasons but this are the only one I am aware off. For example your application is multithreading. I think mappoint is thread safe, but I hope you dont access same mappoint instance from more than 1 thread, or does not call some methods from within a different thread context that the thread that created mappoint (normally UI thread).

__________________
rgds, Wilfried Mestdagh
www.mestdagh.biz
MapPoint coding demo
Order MapPoint 2009 with Routing and User Tools Spreadsheet

Thanks a lot for your reply.
The problem is that I call some methods from different threads.
I probably solved my problem using a VB.NET "Mutex" class to syncronize different threads.

In your opinion, would it be a solution declare MapPoint variable as "Shared"?

Thanks a lot again
Matteo

Hi Matteo,

Declaring as shared is in my opinion not a solution. You indeed probably solved the problem with synchronizing your threads. But I also think it is only temporary solved.

If you create a component in a particular thread context, normally you have to call all his events also from within same thread context. Synchronizing does not help, the context is what matters.

Note that synchronizing threads is actually disable multithreading

If you really need thread, then I advice if you wants to call mappoint methods then do it in main thread context. The most easy way to do it is to PostMessage to the main thread. Then the custom message handler do the call.

in dotNet you can easy P/Invoke this win32API call. I think in version 2 they have done it theirselve but I still use my own.

__________________
rgds, Wilfried Mestdagh
www.mestdagh.biz
MapPoint coding demo
Order MapPoint 2009 with Routing and User Tools Spreadsheet

Thanks a lot for your help, Wilfried
Now I will think about the situation.
Bye Matteo.