Cannot put "default" to switch block

Question

I have looked at the similar questions and answers, but i still cannot see the problem in my code. I have a switch statement and here it is:

switch (header)
        {
            case Headers.Queue:
                {
                    int id = pr.ReadInt32();
                    string fileName = pr.ReadString();
                    long length = pr.ReadInt64();

                    TransferQueue queue = TransferQueue.CreateDownloadQueue(this, id, Path.Combine(downloadDirectory,
                        Path.GetFileName(fileName)), length);

                    _transfers.Add(id, queue);

                    if (Queued != null)
                    {
                        Queued(this, queue);
                    }
                }
                break;
            case Headers.Start:
                {
                    int id = pr.ReadInt32();

                    if (_transfers.ContainsKey(id))
                    {
                        _transfers[id].Start();
                    }
                }
                break;
            case Headers.Chunk:
                {
                    int id = pr.ReadInt32();
                    long index = pr.ReadInt64();
                    int size = pr.ReadInt32();
                    byte[] buffer = pr.ReadBytes(size);

                    TransferQueue queue = _transfers[id];

                    queue.Write(buffer, index);

                    queue.Progress = (int)((queue.Transferred * 100) / queue.Length);
                    if (queue.LastProgress < queue.Progress)
                    {
                        queue.LastProgress = queue.Progress;

                        if (ProgressChanged != null)
                        {
                            ProgressChanged(this, queue);
                        }

                        if (queue.Progress == 100)
                        {
                            queue.Close();

                            if (Complete != null)
                            {
                                Complete(this, queue);
                            }
                        }
                    }
                }
                break;
            default:
                {

                }
        }

The problem is, the default block produces an error saying that

Control cannot fall through from one case label ('default:') to another

Can anyone help me with this?

Thanks

take a look at how the switch statement works http://msdn.microsoft.com/en-us/library/06tc147t(v=vs.90).aspx — Ric, Nov 16 '13 at 14:29
possible duplicate of [Switch statement fallthrough in C#?](http://stackoverflow.com/questions/174155/switch-statement-fallthrough-in-c) — Sriram Sakthivel, Nov 16 '13 at 14:31
I suggest that you refactor the code into a switch which simply calls a different method for each case. That switch itself is over 60 lines long. This will make it easier for you to debug and maintain. Also, refactoring is fun! If you don't want to pollute you class namespace with three additionally functions, you can use nested functions or a dispatch dictionary. — Aluan Haddad, Nov 16 '13 at 15:07

score 5 · Accepted Answer · edited Nov 16 '13 at 14:30

5

You should add break; for the default case as well.

edited Nov 16 '13 at 14:30

Hanky Panky

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answered Nov 16 '13 at 14:29

Jens Kloster

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Not really, you can have `return`, `throw` etc – Sriram Sakthivel Nov 16 '13 at 14:31
"You should add break;" I feel that is not true. You can add `break` sounds better IMO. – Sriram Sakthivel Nov 16 '13 at 14:35

Sudhakar Tillapudi · Answer 2 · 2013-11-16T14:41:48.430

3

Each switch case is required to have transfer control [break,return,throw] as it does not allow fall through.

add break (asper your code) for your default case too as beow:

default:
        {

        }
break;

edited Nov 16 '13 at 14:41

answered Nov 16 '13 at 14:31

Sudhakar Tillapudi

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@SriramSakthivel: Thank you for your valuable inputs. – Sudhakar Tillapudi Nov 16 '13 at 14:42
and you can certainly have goto and infinite loop also. Compiler will be happy to compile with that :) – Sriram Sakthivel Nov 16 '13 at 14:43
:) yes yes Thank you ,but it is strange that compiler can identify the infinite loops at compile time and accepting it in place of break or return statements. – Sudhakar Tillapudi Nov 16 '13 at 14:45
No, it does it compile time. If it can't find in compiletime it will complain you.. – Sriram Sakthivel Nov 16 '13 at 14:47
sorry typo ,imean in compiletime :) – Sudhakar Tillapudi Nov 16 '13 at 14:47
Yep.. It does it usually. nothing strange. You'd have seen "unreachable code detected" warning when compiler see some infinite loop.. – Sriram Sakthivel Nov 16 '13 at 14:49
yes yes i see. so can we say" anyblock of code which get rid of the current case is fine to have ", please correct me if i'm wrong. – Sudhakar Tillapudi Nov 16 '13 at 14:50
I'd say like this. Any statement which doesn't fall through is fine for compiler IMO. – Sriram Sakthivel Nov 16 '13 at 14:51
Okay Thanks nice to meet you here :) – Sudhakar Tillapudi Nov 16 '13 at 14:57

Cannot put "default" to switch block

2 Answers2