[c#] ?: ?? Operators Instead Of IF|ELSE

public string Source
{
    get
    {
        /*
        if ( Source == null ){
            return string . Empty;
        } else {
            return Source;
        }
        */
        return Source ?? string.Empty;
    }
    set
    {
        /*
        if ( Source == null ) {
            Source = string . Empty;
        } else {
            if ( Source == value ) {
                Source = Source;
            } else {
                Source = value;
            }
        }
        */
        Source == value ? Source : value ?? string.Empty;
        RaisePropertyChanged ( "Source" );
    }
}

Can I use ?: ?? operators EXACTLY as If/Else?

My Question :
How to write the following with ?: ?? operators

[ 1 ]

if ( Source == null ){
    // Return Nothing
} else {
    return Source;
}

[ 2 ]

if ( Source == value ){
    // Do Nothing
} else {
    Source = value;
    RaisePropertyChanged ( "Source" );
} 

Briefly : How to do nothing, return nothing and do multiple instructions with ?: ?? operator?

the ?: is the itinerary operator. (believe i spelled that properly) and it's simple to use. as in a boolean predicate ? iftrue : ifalse; But you must have a rvalue/lvalue as in rvalue = predicate ? iftrue: iffalse;

ex int i = x < 7 ? x : 7;

if x was less than 7, i would get assigned x, if not i would be 7.

you can also use it in a return, as in return x < 7 ? x : 7;

again, as above , this would have the same affect.

so, Source = Source == value ? Source : string.Empty; i believe is what your trying to acheive.

If you are concerned with the verbosity of your code I would write this rather than trying to abuse expressions.

if (Source == value) return;
Source = value;
RaisePropertyChanged("Source");

The "do nothing" doesn't really work for ?

if by // Return Nothing you actually mean return null then write

return Source;

if you mean, ignore the codepath then write

 if ( Source != null )
            {
                return Source;
            }
// source is null so continue on.

And for the last

 if ( Source != value )
            { Source = value;
                RaisePropertyChanged ( "Source" );
            }

// nothing done.

Refering to ?: Operator (C# Reference)

The conditional operator (?:) returns one of two values depending on the value of a Boolean expression. Following is the syntax for the conditional operator.

Refering to ?? Operator (C# Reference)

The ?? operator is called the null-coalescing operator and is used to define a default value for a nullable value types as well as reference types. It returns the left-hand operand if it is not null; otherwise it returns the right operand.

That means:

[Part 1]

return source ?? String.Empty;

[Part 2] is not applicable ...

I don't think you can its an operator and its suppose to return one or the other. It's not if else statement replacement although it can be use for that on certain case.

The ternary operator (?:) is not designed for control flow, it's only designed for conditional assignment. If you need to control the flow of your program, use a control structure, such as if/else.

The ?: Operator returns one of two values depending on the value of a Boolean expression.

Condition-Expression ? Expression1 : Expression2

Find here more on ?: operator, also know as a Ternary Operator:

• http://net-informations.com/csprj/statements/cs-operator.htm

The ternary operator RETURNS one of two values. Or, it can execute one of two statements based on its condition, but that's generally not a good idea, as it can lead to unintended side-effects.

bar ? () : baz();

In this case, the () does nothing, while baz does something. But you've only made the code less clear. I'd go for more verbose code that's clearer and easier to maintain.

Further, this makes little sense at all:

var foo = bar ? () : baz();

since () has no return type (it's void) and baz has a return type that's unknown at the point of call in this sample. If they don't agree, the compiler will complain, and loudly.