Chapter 9 - Structured Error Handling

'System.Windows.Forms.Control.x' is not accessible in this context because it is 'Private'.

'System.Windows.Forms.Control.y' is not accessible in this context because it is 'Private'.

Name 'Z' is not declared.

These messages don't point very directly to what's wrong, so let's just get right to the problem. Both the Try and the Catch blocks are separate coding blocks in VB.NET and can't share variables unless you code them to do that. So, because X, Y, and Z are declared in the Try block, they are not available in the Catch block. To solve the problem, just move them outside both blocks.

~~~~~~~~~~~~~~~~~~~~~~~~~
Dim X, Y, Z As Integer
Try
   ' The traditional Divide By Zero error
   X = 1 : Y = 0
   Z = X / Y
Catch ex As Exception
   Debug.WriteLine("exception using X, Y, and Z values" _
   & vbCrLf & vbTab & X & Y & Z)
End Try
~~~~~~~~~~~~~~~~~~~~~~~~~

• Structure FINALLY comes to VB Error Handling!
• Exceptions to the Book! - A typo - And a more significant 'exception'
• Microsoft's Point of View
• The Difference in Code
• The Microsoft Way - Here's the Microsoft documentation method
• About the New Tricks
• What Could Go Wrong? - A Few Things That Might Be Confusing
• About the Error Messages
• Confusion in Disk Drive Error Handler ?
• Assignment For Next Time