What is the benefit and model usage of the C# label

Question

Duplicate:

What is the use of labels in c#?

I was trawling through some .NET Source Code using reflector when I came across something which I see very little of on the web, which is the label syntax.

From here I can see that it raises the chance of ugly spaghetti code:

goto 1: 
goto 2: 
if(booleanProperty) goto 1:

Is the purpose of the label simply so you can jump back and fourth inside a function?

What model usages of the C# label would you say there is? Do you have any experience with its implementation yourself? Was it a good experience or not?

if (1 == 1)
    goto Stage2;
Stage1:
    Console.WriteLine("Stage1");
Stage2:
    Console.WriteLine("Stage2");

Answer 1

Goto is highly controversial. However, the code you encountered was probably refactored from a more readable c# source code into labels and branches which more closely aligns with the IL structures.

Answer 2

There are a very few situations - usually within autogenerated code representing a state machine - where goto can make life simpler. There's usually a way round it if you think hard enough, but for autogenerated code it's easier to work out a simple but less readable way of doing it than try to generate the code you'd write by hand.

Can't say I've used it myself in C#, but IIRC I did something similar when porting the Colossal Cave adventure to Java.

Answer 3

The only time I've found the label/goto syntax useful in C# is when implementing fall-through in case statements. This is something that I found occasionally useful in Java that C# doesn't allow. Otherwise I avoid labels and goto like the plague.

Answer 4

You see this in reflector most often because the programmer used a higher-level construct that was re-written behind the scenes so we now see goto/labels instead.

When considering whether to use a label as a programmer, my rule of thumb is that if you have to ask you probably shouldn't do it.

Answer 5

there are various usages of goto, taking into account, always avoid spaghetti code, and all the advice in previous responses:

    while (loop1) {
    while (loop2) {
     if (timeToQuit) 
      break outerLabel;
    }
}
outerLabel:

In a Switch

switch(value) {
    case 1:
     // DoSomething();
     break;
    case 2:
     // DoSomethingElse();
     break;
    default:
     goto case 1;
}

Answer 6

Benefit: job security? -- because it can really make your code unreadable to anyone else

Usage model: none, unless the alternative is even worse