Unstructured Exception Handling in VB.net

By: Steven Holzner Emailed: 1698 times Printed: 2200 times    

Latest comments
By: rohit kumar - how this program is work
By: Kirti - Hi..thx for the hadoop in
By: Spijker - I have altered the code a
By: ali mohammed - why we use the java in ne
By: ali mohammed - why we use the java in ne
By: mizhelle - when I exported the data
By: raul - no output as well, i'm ge
By: Rajesh - thanx very much...
By: Suindu De - Suppose we are executing

The old error-handling mechanism in VB6 and before is now called unstructured exception handling, and it revolves around the On Error Goto statement. You use this statement to tell VB .NET where to transfer control to in case there's been an exception, as in this case, where I'm telling Visual Basic to jump to the label "Handler" if there's been an exception. You create labels in your code with the label name followed by a colon, and the exception-handling code will follow that label (note that I've added an Exit Sub statement to make sure the code in the exception handler is not executed by mistake as part of normal program execution):

Module Module1
    Sub Main()
        On Error Goto Handler
        
        Exit Sub
Handler:
        
    End Sub
End Module

Now I can execute some code that may cause an exception, as here, where the code performs a division by zero, which causes an exception. When the exception occurs, control will jump to the exception handler, where I'll display a message and then use the Resume Next statement to transfer control back to the statement immediately after the statement that caused the exception:

Module Module1
    Sub Main()
        Dim int1 = 0, int2 = 1, int3 As Integer
        On Error Goto Handler
        int3 = int2 / int1
        System.Console.WriteLine("The answer is {0}", int3)
Handler:
        System.Console.WriteLine("Divide by zero error")
        Resume Next
    End Sub
End Module

When you run this code, you see this message:

Divide by zero error

VB.net Home | All VB.net Tutorials | Latest VB.net Tutorials

Sponsored Links

If this tutorial doesn't answer your question, or you have a specific question, just ask an expert here. Post your question to get a direct answer.



Bookmark and Share

Comments(1)


1. View Comment

please gave us simple difference between structured and unstructured exception handling

View Tutorial          By: vishal at 2011-12-18 13:33:17

Your name (required):


Your email(required, will not be shown to the public):


Your sites URL (optional):


Your comments:



More Tutorials by Steven Holzner
Changes in Controls from VB6 to VB.net
Throwing a Custom Exception in VB.net
Throwing an Exception in VB.net
Using Finally in VB.net
Using Multiple Catch Statements in VB.net
Exception Filtering in the Catch Block in VB.net
Raising an Exception Intentionally in VB.net
Getting an Exception's Number and Description in VB.net
Using On Error GoTo 0 in VB.net
Using Resume Next and Resume Line in VB.net
Understanding Scope in VB.net
Properties in VB.net
Procedure Delegates in VB.net
Preserving a Variable's Values between Procedure Calls in VB.net
Specifying Optional Arguments with default values in Procedures in VB.net

More Tutorials in VB.net
Scope in VB.net
Unstructured Exception Handling in VB.net
Structured Exception Handling in VB.net
Creating Sub Procedures in VB.net
Creating Functions in VB.net
Passing a Variable Number of Arguments to Procedures in VB.net
Specifying Optional Arguments with default values in Procedures in VB.net
Preserving a Variable's Values between Procedure Calls in VB.net
Procedure Delegates in VB.net
Properties in VB.net
Understanding Scope in VB.net
Using Resume Next and Resume Line in VB.net
Using On Error GoTo 0 in VB.net
Getting an Exception's Number and Description in VB.net
Raising an Exception Intentionally in VB.net

More Latest News
Most Viewed Articles (in VB.net )
What's New in VB .NET? A comparison of VB vs VB.net
Debug and Release Versions in .NET
Assemblies, Solutions and Projects in VB .NET
Visual Basic Statements
Arrays and Dynamic Arrays in VB.net
Operators in VB.net
String Split function in VB.net
To read the entire worksheet in an Excel workbook through VB.net Code
Using Excel 2007 DataBar in VB.net
Insert cell data in an Excel file using OLEDB in VB.net
How to export from DataGridView to excel using VB.net
Your first VB.NET Crystal Reports - A step by step guide
How to send email using VB.NET code
How to find IP Address of Host using .net code
Multi Threaded Client Socket Programming in VB.net
Most Emailed Articles (in VB.net)
What is .NET Framework and the Common Language Runtime?
Create an Excel 2007 file in VB.NET 2005
Insert Pictures in Excel 2007 from VB.NET 2005
How to export from database to excel using VB.net
Using the ServiceBase Class in VB.net
Changes in Controls from VB6 to VB.net
While Loop in VB.net
String Insert, index off & format in VB.net
Substring in Vb.Net String Class
String Split function in VB.net
Vb.net text reader
Using Excel 2007 Chart VB.net Picture Box
Using Excel 2007 DataBar in VB.net
Insert cell data in an Excel file using OLEDB in VB.net
Your first VB.NET Crystal Reports - A step by step guide