What is the proper use of keyword 'this' in private class members?

Question

When should the keyword 'this' be used within C# class definitions?

Is it standard to use the form "this.Method()" from within class? Or to just use "Method()"? I have seen both, and usually go with the second choice, but I would like to learn more about this subject.

Answer 1

Most of the time it is redundant and can be omitted; a few exceptions:

• to call a chained constructor: Foo() : this("bar") {}
• to disambiguate between a local argument/variable and a field: this.foo = foo; etc
• to call an extension method on the current instance: this.SomeMethod(); (where defined as public static SomeMethod(this Foo foo) {...})
• to pass a reference to the current instance to an external method: Helper.DoSomething(this);

Answer 2

this is mainly used to explicitly use a class member when the name alone would be ambiguous, as in this example:

public class FooBar
{
    private string Foo;
    private string Bar;

    public void DoWhatever(string Foo, string Bar)
    {
        // use *this* to indicate your class members
        this.Foo = Foo;
        this.Bar = Bar;
    }

    public void DoSomethingElse()
    {
        // Not ambiguity, no need to use *this* to indicate class members
        Debug.WriteLine(Foo + Bar);
    }
}

Aside from that, some people prefer to prefix internal method calls (`this.Method()´) because it makes it more obvious that you are not calling any external method, but I don't find it important.

It definitely has no effect on the resulting program being more or less efficient.

Answer 3

I use 'this' when it becomes ambigious what your refering to, it having a local variable with the same/similar name to a class variable/method.

But its really a personal preference thing, just use what you feel is best.

Answer 4

always... just my 2 cents