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When it comes to fields, the rule to code
by is to make all fields private, and

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then write public getters and
setters that access it indirectly.

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We just learned how to write accessor
methods in the previous video.

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You can imagine this forces you to
write a lot of additional code.

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Two methods for every field.

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Fortunately, C# has some syntactic sugar
that makes it much easier to write

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accessors like these.

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It's called a property.

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We can replace these two
methods with the property.

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I'll write the property down here so

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we can see the differences
between methods and properties.

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First, we give the property
an access modifier.

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I'll make it public.

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Then we give it it a type.

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The type should match
the type of the field.

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Now we give it the name.

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I'll name it location.

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Inside the curly braces,
we'll write our getter and our setter.

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The getter will do exactly what
the get location method up here did,

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it will just return the field.

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The setter will do exactly
what the set location did,

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it will set the location field.

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Properties have the same benefits that
we got from having these two methods.

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They have a getter and a setter.

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They correspond to these two methods.

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In the case of the setter,
the value parameter is implied.

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Value is just a variable that stores
the value being assigned to the field.

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You can think of these
as two separate methods.

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In fact, behind the scenes,

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properties look identical to these
two methods we wrote up here.

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They're used differently, though.

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Let's go to main and compare using
methods with using properties.

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Let's clear out this code first.

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Now let's make an invader.

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So let's say Invader.

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Equals Invader.

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Let's also make a new map location.

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So map location, I just call it location,
equals new map location

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and pass in that would be at 0,
0 and pass in the map.

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There we go.

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[BLANK] So

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to use the invaders Set Location Method
to set the location,

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we call the Set Location Method and
pass in this location.

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When using a property instead,
we can just assign location a new value.

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So we can just say
invader.location = location.

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This is not setting the location
field directly, though.

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Instead, it's calling the setter inside
the location property, right here.

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We can even add additional code here.

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So say we wanted to print something
every time the location changed.

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So we could say, system.console.rightline.

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Location changed.

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So the same goes for getters.

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We can call the property getter in
the same way we would read a field.

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So we could say location
= invader.location.

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So this gets the location
from the invader and

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sets it back into the local
variable location.

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Not very practical, but this is just for
demonstration purposes.

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So now that we have a property we
can delete these two methods here.

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And we don't need to do anything in the
setter other than just set the location.

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Pretty nifty.

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As you can see,

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properties support the encapsulation
principles of object oriented programming.

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They allow us to hide how
an invader's location is represented

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in the class internally.

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This allows us to make
changes to the class without

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affecting the users of the class.

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We'll see many more examples of how
to use properties as we go forward.

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We'll also learn how to use properties
to do even better encapsulation.