Deriving from the Process class.

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yitz - 08 Feb 2005 08:47 GMT

I would like to associate an object derived from the
System.Diagnostics.Process class with an existing process.
Something like this:

public class MyProcess : System.Diagnostics.Process
{
}
MyProcess p = MyProcess.GetProcessById(processID) ; // NOT VALID

The assignment however is not valid since the GetProcessById() method
returns a (base) Process object which cannot be assigned to a (derived)
MyProcess object. Is there any way to associate the derived class
object with an existing process?

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cody - 08 Feb 2005 09:52 GMT

What you want is covariant return types that is overridden methods can
return subclasses from the original return type but this is not supported in
C# yet but I really hope it will in the future.

> I would like to associate an object derived from the
> System.Diagnostics.Process class with an existing process.
[quoted text clipped - 9 lines]
> MyProcess object. Is there any way to associate the derived class
> object with an existing process?

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Fabian Schmied - 09 Feb 2005 09:19 GMT

> What you want is covariant return types that is overridden methods can
> return subclasses from the original return type but this is not
> supported in
> C# yet but I really hope it will in the future.

That wouldn't change anything. GetProcessById is a static method
implemented by the Process class and it always creates a Process object.
With or without covariant return types, you cannot transform this into a
MyProcess object.

The best I can think of would be to wrap the Process instance in you
MyProcess object, i.e.

MyProcess p = new MyProcess(Process.GetProcessById(processID));

Fabian

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cody - 09 Feb 2005 11:59 GMT

> > What you want is covariant return types that is overridden methods can
> > return subclasses from the original return type but this is not
[quoted text clipped - 10 lines]
>
> MyProcess p = new MyProcess(Process.GetProcessById(processID));

Oh I misunderstood, yes in case of a static method covariance won't help but
you can define a new method with the same name as the inherited class

public static new MyProcess GetProcessById(int pid)
{
return new MyProcess (Process.GetProcessById(pid));
}

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Deriving from the Process class.

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