To quote from an MSDN blog, When the STAThreadAttribute is applied, it changes the apartment state of the current thread to be single threaded. Without getting into a huge discussion about COM and threading, this attribute ensures the communication mechanism between the current thread and other threads that may want to talk to it via … Read more
This is more a Windows requirement than a WPF one, and goes back to the original design of Windows forms and controls, from before .NET. STAThread refers to “Single-Threaded Apartments” which refers to the threading model used by the current (main) thread. The threading model in use dictates how other .NET and COM applications will … Read more
Services are run by the windows service hosting system, which runs using MTA threads. You can’t control this. You have to create a new Thread and set its ApartmentState to STA, and do your work on this thread. Here’s a class that extends ServiceBase that does this: public partial class Service1 : ServiceBase { private … Read more
You can start STA Threads like so: Thread thread = new Thread(MethodWhichRequiresSTA); thread.SetApartmentState(ApartmentState.STA); //Set the thread to STA thread.Start(); thread.Join(); //Wait for the thread to end The only problem is that your result object must be passed along somehow.. You can use a private field for that, or dive into passing along parameters into threads. … Read more
This is not possible, BGW uses a threadpool thread. TP threads are always MTA, it cannot be changed. You will have to use a regular Thread, call SetApartmentState() before you start it. This thread also should pump a message loop, call Application.Run(). Maybe you ought to consider calling this code from the UI thread. Because … Read more
Apartment threading is a COM concept; if you’re not using COM, and none of the APIs you call use COM “under the covers”, then you don’t need to worry about apartments. If you do need to be aware of apartments, then the details can get a little complicated; a probably-oversimplified version is that COM objects … Read more
The problem you’re running into is that most background thread / worker APIs will create the thread in a Multithreaded Apartment state. The error message indicates that the control requires the thread be a Single Threaded Apartment. You can work around this by creating a thread yourself and specifying the STA apartment state on the … Read more
Keep in mind that the message queue that Windows creates for an STA thread is already an implementation of a thread-safe queue. So just use it for your own purposes. Here’s a base class that you can use, derive your own to include your COM object. Override the Initialize() method, it will be called as … Read more