C#: does using ref/out for a method parameter make any difference if an object variable is being passed? [duplicate]

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Passing By ref and out

C#: does using ref/out for a method parameter make any difference if an object variable is being passed?

In C#, an object variable passes only a reference to the method, which means it is already a ref/out parameter. Is this correct?

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The instance is passed by reference. The pointer to the instance is passed by value, though.

If you use ref, the pointer is passed by reference as well - therefore you can use:

private void CustomDispose(ref object x) { x.Dispose(); x = null; }

CustomDispose(ref someInstance.someField);

someInstance's field will be assigned to null. It might be useful in Disposing via a custom method for example.

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To confirm the first part of your question:

• when dealing with an object (instance) in .NET, you always deal with 2 entities: the actual, anonymous object and the named reference to that object. That reference is a field, variable or parameter.

• You cannot pass the object instance as a parameter at all, you can only pass the reference.

• You can pass a reference by reference, meaning you can make it point somewhere else

 

void SetNull(ref MyObject parameter)  
{ 
   parameter = null;  // would make no sense w/o the ref
}