Throw statement

[marcmc]

I cannot get my throw statement to run. The program hits
the 1 and 3 message boxes but not 2. I have included
Imports System.Exception
Imports Microsoft.VisualBasic

Private Sub btnLogError_Click(ByVal sender As
System.Object, ByVal e As System.EventArgs) Handles
btnLogError.Click
Dim at As New ErrorClassTest
Try
MessageBox.Show("1")
Throw New System.Exception("An error has
occurred")
MessageBox.Show("2")
Catch ex As Exception
MessageBox.Show("3")
If Not (at.LogError("\My Documents\Exception
Handler.log", _
ex.Message.ToString, _
"btnLogError_Click", _
"Testing Log File....")) Then
MessageBox.Show("Could not write to the
Log File", MessageBoxIcon.Exclamation)
End If
End Try
End Sub

 

[William Ryan]

Once you throw your System.Exception, execution shifts to the handler which
in turn causes 3 to show.

 

[marcmc]

Thats fair enough but the throw statement is not
executing, something should be thrown to the screed,
correct?

I also have an ErrorHandlerClass which should right this
exception to a log file when it occurs but obviously does
not because its not executed.
I got this out of a book and copied it meticulously and
it still wont work. Its 1 screen, 1 button, 1 class and a
click event on the button. Very simple you would think!!
Any further ideas?

 

[Chris Tacke, eMVP]

If you're seeing 1 and 3, then the throw is executing - it's then getting
caught by the try/catch block and properly moving into the catch.

 

[marcmc]

fair enough again but nothing is happening in my log file.

my class is as follows, am i missing something very
simple?

Imports Microsoft.VisualBasic
Imports System.Exception
Public Class ErrorClassTest
Function LogError(ByVal LogFile As String, ByVal
Message As String, _
ByVal Source As String, ByVal Comments As String)
As Boolean

Dim strLogRecord As String
Dim sw As System.IO.StreamWriter

Try
' Open the log()
sw = New System.IO.StreamWriter(LogFile, True)

' Add item to the log
strLogRecord = Now.ToString & "|" & Message
& "|" & Source & _
"|" & Comments & "|"
sw.WriteLine(strLogRecord)

'Close the log
sw.Close()

'Return a positive result
LogError = True

' A runtime error was generated. Return a
negative result.
Catch
LogError = False
End Try
End Function
End Class

 

[Ginny Caughey [MVP]]

marcmc,

What is the value of LogError?If it is false, an error occurred when you
were trying to write to the log file and the try...catch block caught it for
you.

 

[marcmc]

got it thanks