Question

I am trying to build an error handler for my desktop application. The code Is in the class ZipCM.ErrorManager listed below.

What I am finding is that the outputted file is not giving me the correct info for the StackTrace.

Here is how I am trying to use it:

Try
     '... Some stuff here!

     Catch ex As Exception
            Dim objErr As New ZipCM.ErrorManager
            objErr.Except = ex
            objErr.Stack = New System.Diagnostics.StackTrace(True)
            objErr.Location = "Form: SelectSite (btn_SelectSite_Click)"
            objErr.ParseError()
            objErr = Nothing
        End Try

Here is the class:

    Imports System.IO

Namespace ZipCM

    Public Class ErrorManager

        Public Except As Exception
        Public Location As String
        Public Stack As System.Diagnostics.StackTrace

        Public Sub ParseError()
            Dim objFile As New StreamWriter(Common.BasePath & "error_" & FormatDateTime(DateTime.Today, DateFormat.ShortDate).ToString().Replace("\", "").Replace("/", "") & ".log", True)
            With objFile
                .WriteLine("-------------------------------------------------")
                .WriteLine("-------------------------------------------------")
                .WriteLine("An Error Occured At: " & DateTime.Now)
                .WriteLine("-------------------------------------------------")
                .WriteLine("LOCATION:")
                .WriteLine(Location)
                .WriteLine("-------------------------------------------------")
                .WriteLine("FILENAME:")
                .WriteLine(Stack.GetFrame(0).GetFileName())
                .WriteLine("-------------------------------------------------")
                .WriteLine("LINE NUMBER:")
                .WriteLine(Stack.GetFrame(0).GetFileLineNumber())
                .WriteLine("-------------------------------------------------")
                .WriteLine("SOURCE:")
                .WriteLine(Except.Source)
                .WriteLine("-------------------------------------------------")
                .WriteLine("MESSAGE:")
                .WriteLine(Except.Message)
                .WriteLine("-------------------------------------------------")
                .WriteLine("DATA:")
                .WriteLine(Except.Data.ToString())
            End With
            objFile.Close()
            objFile = Nothing
        End Sub

    End Class

End Namespace

What is happenning is the .GetFileLineNumber() is getting the line number from objErr.Stack = New System.Diagnostics.StackTrace(True) inside my Try..Catch block. In fact, it’s the exact line number that is on.

Any thoughts of what is going on here, and how I can catch the real line number the error is occuring on?

Answer 1

Edit: Changed the code to account for the Exception.StackTrace being a string rather than a real StackTrace

You’re creating a new StackTrace, so then it will be for the line you’re declaring it on, if you want the line number of the original exception, use the stack trace in Exception.StackTrace.

I think you’re being a little confused, I can’t see why you create the new StackTrace at all?

Edit: Added more bits to the answer here since easier to see the syntax than in a comment

Currently you have the line

 objErr.Stack = New System.Diagnostics.StackTrace(True)

Which means that you’re creating a whole new stacktrace, starting when you’re creating it.

Instead change that line to:

objErr.Stack = New System.Diagnostics.StackTrace(ex, True)

Which will have the stacktrace from when the error actually happened.

Edit: Added complete sample:

Private Sub a1()
    Try
        a2()
    Catch ex As Exception
        Dim st As New StackTrace(True)
        Debug.WriteLine(String.Format("ST after exception, will give line number for where st was created. Line No: {0}", st.GetFrame(0).GetFileLineNumber()))

        st = New StackTrace(ex, True)
        Debug.WriteLine(String.Format("ST after exception using exception info, will give line number for where exception was created. Line No: {0}", st.GetFrame(0).GetFileLineNumber()))
    End Try
End Sub

Private Sub a2()
    Dim st As New StackTrace(True)
    Debug.WriteLine(String.Format("ST before exception, will give line number for where st was created. Line No: {0}", st.GetFrame(0).GetFileLineNumber()))
    Dim b As Integer = 0
    Dim a As Integer = 1 / b
End Sub