CODEWITHSUNDEEP
c#loopsmethodscallbackbreak
Nickon
Nickon

Reputation: 10146

Stop method and loop in callback

Question 1. I wonder if it's possible to stop the loop in the inside operation's callback?
Question 2. Can I stop SomeMethod() in the callback?

E.g. I have a code like:

foreach(...)
{
   myObject.SomeMethod(s =>
      {
         // something break-like here to stop foreach/method?
      });
}

[edit]

Here's the example of the code I use - it doesn't work as I want.

bool test = false;
foreach (var drive in drives)
{
    foundFolders.AddRange(
        DirectoryWrapper.GetDirectories(drive, regex, true, s =>
            {
                Dispatcher.Invoke(new Action(() => SetWarningStatus(WarningTypes.Warning,
                                                                    "Looking for backups: " + Environment.NewLine + s.Trim())), DispatcherPriority.Background);
                test = true;
                return;
            }));
    if (test)
        break;
}

Even Resharper says that return is redundant here...

Solution
After @Tigran's suggestion I noticed that always what I should do is to change my GetDirectories definition.

From:

public static IEnumerable<string> GetDirectories(string root, string searchRegex, bool skipSystemDirs = false, Action<string> callback = null) {}

To:

public delegate bool MyCallback(string s);
public static IEnumerable<string> GetDirectories(string root, string searchRegex, bool skipSystemDirs = false, MyCallback callback = null)

Then I can return a flag inside a callback function and serve it inside GetDirectories().

Btw. what's interesting, when we have our "GetDirectories" as a binary, then we probably can't stop it in delegate... We have to wait until its execution finishes.

Upvotes: 0

Views: 1211

Answers (1)

Tigran
Tigran

Reputation: 62248

Question 1:

You can if use the variable which will be captured by lambda. Like: 

foreach(...)
{
   var stopIteration  =false;    
   myObject.SomeMethod(s =>
      {
          ...

          stopIteration   = true; //due the some condition
      });

   if(stopIteration)break;
}

Question 2:

Just use return

myObject.SomeMethod(s =>
{
     //something gone wrong, or need exit; 
      return;
});

Upvotes: 3

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