A Technical Debtor

I got the following question via e-mail:

I want to catch timeout errors when I execute a script. Catching the error is easy, but I then want to retry 3 times. In VB6 I could just resume a command when I caught the error. How can I do this with vb 2008 using try..catch?

This is a case where two different techniques come into play. The first is using a number of Catch statements to allow you to catch specific types of exceptions. The second is to make essentially a recursive call to the function, with a counter to ensure that you don't end up in an infinite loop.

  1: Module Module1
  2:     Sub Main()
  3:         Foo()
  4:         Console.ReadLine()
  5:         Foo()
  6:         Console.ReadLine()
  7:     End Sub
  8: 
  9:     Private tryCounter As Integer = 0
 10:     Private maxAttempts As Integer = 3
 11:     Private Sub Foo()
 12:         Try
 13:             If tryCounter = maxAttempts Then tryCounter = 0
 14:             tryCounter += 1
 15:             FooWithTimeout()
 16:         Catch toex As TimeoutException
 17:             If tryCounter = maxAttempts Then
 18:                 Console.WriteLine("Too many failures.")
 19:             Else
 20:                 Foo()
 21:             End If
 22:         Catch ex As Exception
 23:             Throw
 24:         End Try
 25:     End Sub
 26: 
 27:     Private Sub FooWithTimeout()
 28:         Console.WriteLine("Attempt " & tryCounter)
 29:         Throw New TimeoutException
 30:     End Sub
 31: End Module

• Share This Post:
• 
• 
• 
•   Short Url: http://wblo.gs/XJ1