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C# C# Objects Encapsulation with Properties Expression Bodied Members

Ranvir Sahota
Ranvir Sahota
9,844 Points
Posted by Ranvir Sahota
Ranvir Sahota
9,844 Points

public MapLocation Location => path.GetLocation(pathStep); How does it know to get?

The question is in the title. How do expression bodies members know the statement is for, get not set? Can you do the same for set? Please provide an example if it can be done. How does the compiler know path.GetLocation(pathStep) is to be returned?

2 Answers

luke hammer
luke hammer
25,513 Points
luke hammer
luke hammer
25,513 Points

He covers this quickly at

timestamp 1:40 "Location is still a property. The Location property reduces to just calling _path.GetLocationAt. So long as this part on the right side evaluates to a MapLocation, and you can write it in a single statement, then you can write it like this."

So i think the key to take away is what is returned by the function you are calling. Get method return the item that you are getting.

However the Set method normally returns void. This cue of what is being returned is what the compiler can see. I'm not aware of away to assume a setter. (i think that would make code very hard to read.

but here is an example of adding a setter to that line 

    public MapLocation Location { get => _path.GetLocationAt(_pathStep); set => Location = value ; }
Ranvir Sahota
Ranvir Sahota
9,844 Points
Ranvir Sahota
Ranvir Sahota
9,844 Points

So basically there is no shorthand for set. And get always returns something when set doesn't, otherwise they wont getters and setters. Thanks

drstrangequark
drstrangequark
8,273 Points
drstrangequark
drstrangequark
8,273 Points

So basically, this shorthand is only useful in relatively simple instances, correct? If you need to add additional code to "get" or "set" you should write it out longhand?

luke hammer
luke hammer
25,513 Points
luke hammer
luke hammer
25,513 Points

My rule of thumb is that if the whole line 

public MapLocation Location { get => _path.GetLocationAt(_pathStep); set => Location = value ; }

Does not fit on a single line then use a more traditional setter or getter.

but in my experience, if your get or set is so long you can not declare it on a single line There is a good change you need to abstract to a different method or function anyway.

This code is a good example of this.

with it using a _path.GetLocationAt() function.