Is there a way to use the same method (without overloading) without passing the parameter as ref?
Yes, but this feature probably won't help you.
In C # 4, it will not be necessary to use "ref" to invoke a COM object that accepts an optional ref parameter.
, COM-, VB6. VB6 ref. # , , # :
object missing = Type.Missing;
object abc = 10;
foo.Blah(ref missing, ref missing, ref missing, ref abc, ref missing);
. # 4
foo.Blah( whatever : 10 );
ref whatnot .
COM- # 4. "ref", .