Continue code after exception

Question

I would like to know if there is a way for the program to continue after the exception is thrown. For example:

Try line 1 line 2 line 3 line 4 ( here the exception is thrown and jumps to the catch) line 5 <-- i would like the program to continue its execution loging the error line 6 Catch ex as Exception log(ex.tostring) End Try 

Thanks.

Answer 1

If you are doing something that you know how to recover or it is not vital, you should only transfer this line to try / catch with a certain catch. eg.

 Try line 1 line 2 line 3 Try line 4 ( here the exception is throw and jumps to the catch) Catch iox as IOException ' or whatever type is being thrown 'log it End Try line 5 <-- i would like the program to continue its execution after loggin the error line 6 Catch ex as Exception log(ex.tostring) End Try 

Answer 2

Use 'Continue For'

Bad practice is everywhere, but useful in some cases, for example. find a file while processing restricted access to certain directories:

  Dim dir As New DirectoryInfo("C:\") Dim strSearch As String = ("boot.ini") For Each SubDir As DirectoryInfo In dir.GetDirectories Try For Each File As FileInfo In SubDir.GetFiles Console.WriteLine("Sub Directory: {0}", SubDir.Name) If File.Name = strSearch Then Console.Write(File.FullName) End If Next Catch ex As Exception Console.WriteLine(ex.Message) Continue For End Try Next 

Answer 3

Although On Error Resume Next is still available in VB.NET , it is mutually exclusive for the preferred method for handling structured exceptions.

Instead, I would recommend using the Finally Try..Catch..Finally block to ensure that Line 5 and Line 6 executed even if row 4 (or any previous row) is selected.

 Try line 1 line 2 line 3 line 4 Catch ex as Exception log(ex.tostring) Finally line 5 line 6 End Try 

Answer 4

VB.net does not support this type of design. Once an exception expands the stack, it cannot be rolled back. Some languages ​​allow you to resume an exception, but this requires more sophisticated stack management - essentially a coroutine.

Answer 5

 try line 1 catch ex as exception log(ex.tostring) end try try line 2 catch ex as exception log(ex.tostring) end try try line 3 catch ex as exception log(ex.tostring) end try try line 4 ( here the exception is throw and jumps to the catch) catch ex as exception log(ex.tostring) end try try line 5 <-- i would like the program to continue its execution after loggin the error catch ex as exception log(ex.tostring) end try try line 6 catch ex as exception end try 

Answer 6

If I'm not mistaken, Exception Guidelines says that if you can check for the error that is most likely to happen, check this condition. If you can check dbnull do it.

Answer 7

Here is a sample code:

 Sub yourSub() Dim cDelegate As CatchDelegate = Sub(ex As Exception) Your Catch Code End Sub line 1 line 2 line 3 TCResumeNext(Sub() line 4, cDelegate) line 5 line 6 End Sub Delegate Sub CatchDelegate(e As Exception) Sub TCResumeNext(tryDelegate As [Delegate], catchDelgate As CatchDelegate) Try tryDelegate.DynamicInvoke() Catch ex As Exception catchDelgate.DynamicInvoke(ex) End Try End Sub 

Answer 8

pretty old post, but for the sake of others. I will personally use "on error resume next", in this case it is a necessary evil