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Threading Model Attribute

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COM+ manages threads for you. Every COM component has a ThreadingModel property that you can specify when you develop the component. This property determines how the component's objects are assigned to threads for method execution.

You can use the Component Services administrative tool to view the threading-model property by right-clicking a component in the Components folder, clicking Properties, and then clicking the Concurrency tab. Under Threading Model, the possible values are as follows:

  • Main Thread Apartment
  • Single Thread Apartment
  • Free Thread Apartment
  • Neutral Apartment
  • Any Apartment

The preferred threading model for COM+ is the neutral apartment. However, if you do not specify a threading model for your component, COM+ uses the main thread apartment, which is the default.

Note

For more detailed information, see Choosing the Threading Model.

 

The following table shows the programming model for apartments in COM+.

Model Apartment Free Both Neutral Not Specified
Single-threaded, not main Created in current apartment Created in multithreaded apartment Created in current apartment Created in neutral apartment Created in main threaded apartment
Single-threaded, main Created in current apartment Created in multithreaded apartment Created in current apartment Created in neutral apartment Created in current apartment
Multithreaded Created in host single-threaded apartment Created in multithreaded apartment Created in multithreaded apartment Created in neutral apartment Created in main threaded apartment
Neutral (on STA thread) Created in host single-threaded apartment for this thread Created in multithreaded apartment Created in neutral apartment Created in neutral apartment Created in main threaded apartment
Neutral (on MTA thread) Created in host single-threaded apartment Created in multithreaded apartment Created in neutral apartment Created in neutral apartment Created in main threaded apartment

 

ThreadingModel