I'm not understanding the usage of C# get; set; seems to be different from Java

I know there are a few questions on stack overflow on this already but I haven't found any that answer my specific question. I came from a java development background and never bothered using the get; set; methods from C# until now.

I have the following code

class Test
{
    public int test { get; set; }
}

In my main function I can declare a new Test and use t.Test = 5 and that works fine; however, when I switch the public to private I cannot access my get; and set; methods anymore... BUT when I use (Similar method to Java)

class Test
{
    private int test;

    public int getTest()
    {
        return this.test;
    }

    public void setTest(int test)
    {
        this.test = test;
    }
}

I'm confused on the design philosophy. In C# should I no longer be using private variables (Only make it private if it's used internally in the class) and make them all public and use private get; private set; to control accessibility?

Jon Skeet
people
quotationmark

When you write this (I'm using different class and property names for clarity):

public class Test
{
    public string Name { get; set; }
}

that's asking the compiler to create a private field with a public property. It's equivalent to:

public class Test
{
    private string name;
    public string Name
    {
        get { return name; }
        set { name = value; }
    }
}

(Except the field name is autogenerated and not directly representable in C#.)

That's basically equivalent to what you'd write in Java as:

// Java
public class Test {
    private String name;

    public String getName() {
        return name;
    }

    public String setName(String name) {
        this.name = name;
    }
}

... but clearly the C# is a lot more compact.

Basically, C#'s properties make for more readable code than having getter and setter methods as normal methods - but that's all they are, really. They're just used differently in code. The automatically implemented properties (as per the first snippet) make "trivial" properties simpler to express. In C# 6, you can write read-only automatically implemented properties too, which can be assigned to from the constructor but only the constructor.

Importantly though, you're still only making the properties part of the public API - not the fields. So if you later want to add some more logic (e.g. to have two properties derived from the same field, or something like that) you can do so without affecting either source or binary compatibility.

people

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