ExportFactory <t，tmetadata - =“”get =“”type =“”of =“”class =“”which =“”derives =“”from =“”t =“”

Answer 1

Because you are storing all the factories in a IEnumerable<ExportFactory<ITask,IMetaData>>, there is no way you can determine the actual type of ITask without executing the factory's CreateExport() method (which I assume you don't want to do yet).

That being said: You are using the ExportFactory<,> with MetaData, so you could expand your IMetaData to contain a TaskType property. That would result in:

IEnumerable<ExportFactory<ITask,IMetaData>> myTasks = ...;
foreach (var task in myTasks)
{
    Type taskType = task.Metadata.TaskType;
}