MEF: an article in The msdn magazine (9) controlling part creation policies ???

Http://msdn.microsoft.com/zh-cn/magazine/ee291628.aspx

DefaultIn this case, all part instances in the container areSingleton,Therefore, all the parts that import them to the container are shared.. Therefore, all the import programs of salesorderview and viewfactory will obtainSame instance. This is required in many cases becauseNo need to have static members on which other components depend. However, sometimes each import program needs to obtain its own instance, for example, to view multiple salesorderview instances on the screen at the same time.

The part creation policy in MEF can be one of the following three values: creationpolicy. Shared, creationpolicy. nonshared or creationpolicy. Any. To specify a part creation policy, use the partcreationpolicy feature to modify the part.

 

[Partcreationpolicy (creationpolicy. nonshared)]
[Export (typeof (isalesorderview)]
Public partial class salesorderview: usercontrol, isalesordderview
{
Public salesorderview ()
{
}
}

 

You can alsoImportSet the requiredcreationpolicy attribute. You can alsoImportSpecifies the partcreationpolicy at the program end.