[vbox-dev] Subject: Com api. Cannot use IDisplay. It's null

[Ivo Smits]

Hi,

VirtualBox 4.2 has introduced a new lock type for VM frontends: 
LockType.LockType_VM. You have to use this lock type, otherwise the 
Console related objects are not initialized.

Ivo

Op 9-3-2013 7:12, Pavel Murygin schreef:
> Hi everybody!
>
> I wrote a virtual box frontend in C# using com api. I haven't touched 
> my code for about a year. During that year I've moved to a laptop from 
> pc. Last time I ran my code it worked fine. Now I cannot access 
> IDisplay because it's null;
> here is my code:
>
>     var vb = new VirtualBoxClass();
>     _machine = vb.FindMachine(machineName);
>
>     var monitors = _machine.MonitorCount;
>
>     Monitors = new MMFFrameBuffer[monitors];
>     for (byte i = 0; i < monitors; i++)
>     {
>         var name = string.Format("monitor{0}", i + 1);
>         Monitors[i] = MMFFrameBuffer.CreateNew(name)
> ;
>     }
>
>     _session = new SessionClass();
>     _machine.LockMachine(_session, LockType.LockType_Shared);
>
>     for (int i = 0; i < MonitorsCount; i++)
>     {
>         _session.Console.Display.SetFramebuffer((uint) i, Monitors[i]);
>     }
>
> My program fails on the line where I'm trying to set framebuffer. I 
> get NullreferenceException: _session.Console.Display is null.
> My current version of Vbox is the latest: 4.2.8 r83876. I can't 
> remember the exact version on which my code ran correctly. I can only 
> say It was the latest one about 1 year ago. Host OS is Win7 pro x64 
> (same as it was on my previous PC)
>
> I'm completely clueless about my issue. Any help would be highly 
> appreciated!
>
> Regrads,
> Pavel Murygin.
>
>
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