Catch as exception

Question

Hello again,

I'm new to using the catch as exception

I need to check and see if I can access a file(the file is in use) So When I try to access it the application crashes. When I can access the file without the application crashing I would like a msgbox to pop up.

Thanks in advance

Answer 1

Catch ex As Exception
   MsgBox(ex.ToString(), MsgBoxStyle.Critical)
End Try

Do you mean like this?

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Samuel - Student - Newbie :]

Answer 2

Hello again,

The way a TryCatch works is that you put any code that my create an error, and any code that depends on that code, in the try section. In the catch section you put code to handle any errors that are thrown from the try section. So in your case you would first put all the file access code in the try section and then in the catch section you would put the code to handle if you cannot access it...something like this:

Dim length As Integer = 0
Try
  length = IO.File.ReadAllBytes("SomeFile").Length
Catch ex As Exception
  ' Some code that will run if you cannot access the file, maybe...
  MessageBox.Show("Unable to Access File")
End Try

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Bill Gates look out!

Answer 3

 

This code will prompt you when the file becomes available for you to open it

 

Public Class Form1

  Dim WithEvents Tm As New Timer
  Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    Tm.Interval = 1000
    Tm.Start()

  End Sub

  Private Sub Tm_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles Tm.Tick

    Try
      Using file As New IO.StreamReader("c:\tst\data.xml")
        Tm.Stop()
        MsgBox("File is available for the application")
      End Using
    Catch ex As Exception
    End Try

  End Sub
End Class