Part 70 Making method parameters optional by using OptionalAttribute Video

hello welcome to prism technologies I am
venket this is part 70 of c-sharp
tutorial in this video we'll discuss
making method parameters optional by
using optional attribute that's present
in system 2 at runtime not interrupt
services namespace please watch part 67
68 and 69 before proceeding with this
video we'll be using the same example
that we used in the previous sessions
let's flip to visual studio so here I
have this add numbers function which
allows us to add two or more numbers so
notice that this function has got three
parameters and at the moment all the
three parameters are mandatory and if
you look at the implementation it's very
straightforward
we have a variable of type integer
result here which is going to hold the
sum of the first and second number and
then here we are checking if rest of
numbers is not now okay that's a third
parameter if it's not null then we know
for sure the user wants to add more than
two numbers in which case we are looping
through each integer that's present in
this array and adding that integer to
our result variable and then finally be
a printing the Sun okay all right now if
I have to invoke this function then I
will have to supply arguments for all
the three parameters let's say for
example I want to add just two numbers
10 and 20 and then if I try to build
this solution as you might expect we get
a compiler error no overload for method
add numbers takes two arguments because
at the moment I only have one version of
add numbers and you know this version
makes all these three parameters
mandatory we have to supply arguments
for all these three parameters okay so
let's see how to use optional attribute
that's present in system return time not
interrupt services namespace to make
this third parameter optional so
obviously the first thing to do is to
import that namespace and how do we do
that using this using declaration so
using system dot runtime dot interrupt
services alright and all that is left
right now is to make this parameter
optional and how do I do that I use that
optional attribute and to specify
attributes we use square
it's so open the square bracket and then
I can say optional you can also use the
you know full name of the class optional
attribute if you want to but attribute
part is optional so I can remove that if
required now look at this then I build
the solution the compliation error goes
away build succeeded now if I run this
as you might expect and what the sum of
the two numbers is going to be 30 so we
just made this third parameter optional
using the optional attribute that's
present in system that runtime dot
Interop services namespace on the other
hand if I want to add let's say five
numbers I can simply you know pass
argument for the third parameter as well
so I'm going to create a new integer
array and then let's say I want to add
30 40 and 50 so obviously when we run
this we get the sum of all those five
numbers all right on this slide you can
find resources for a speed or Nessie
Shaban sequence of interview questions
that's it for today thank you for
listening
have a great day