VB.NET user-defined exception example?

''' 

''' The exception that is thrown when DWM composition fails or is not
''' supported on a particular platform.
''' 

 _
Public Class DwmException: Inherits System.Exception

''' 

''' Initializes a new instance of the  class.
''' 

 Public Sub New()
 MyBase.New()
 End Sub

''' 

''' Initializes a new instance of the  class< br />''' with the specified error message.
''' 

''' The message that describes the error.< br /> Public Sub New(ByVal message As String)
 MyBase.New(message)
 End Sub

''' 

''' Initializes a new instance of the  class
''' with the specified error message and a reference to the inner
''' exception that is the cause of this exception.< br />''' 

''' The message that describes the error.
''' The exception that is the cause of the
''' current exce ption, or a null reference if no inner exception is
''' specified
 Public Sub New(ByVal message As String, ByVal innerException As System.Exception)
 MyBase.New (message, innerException)
 End Sub

 'Constructor required for serialization
  _
 Protected Sub New(ByVal info As SerializationInfo, ByVal context As StreamingContext)
 MyBase.New(info, context)
 End Sub

End Class

Very simply, I want to know if anyone here can give me a user-defined exception in VB.Net Examples. I already have two examples that I can find online, but other than that, I can’t think of anymore. I need to find at least 5 of them to put in my notes and submit them to my teacher.

The two I have so far are: invalid login information (such as incorrect username or password), and expired credit card information for online stores. Any help would be greatly appreciated.

< /p>

The basic requirement is to add a new class inherited from the built-in class System.Exception to the project. This can almost provide you with everything you need for free , Because they are all implemented in the System.Exception class.

The only thing you need to add to the class file is the constructor (because, remember, the constructor is not inherited). Although you don’t have to define all three standard constructors, I strongly recommend that you do this so that your interface is consistent with all the exception classes provided by the .NET Framework. It is not difficult to define them at once, recommended by code analysis tools.

Finally (this is a step most people forget, including those who posted other answers to this question), you need to make your exception serializable. By adding SerializableAttribute to Class declaration and adding the Protected constructor used internally by the serialization mechanism to achieve. This property is not inherited from System.Exception, it must be clearly stated.

Since you asked so well, here is a complete Example, all of the above implementations:

''' 

''' The exception that is thrown when DWM composition fails or is not
''' supported on a particular platform.
''' 

 _
Public Class DwmException: Inherits System.Exception

''' 

''' Initializes a new instance of the  class.
''' 

 Public Sub New()
 MyBase.New()
 End Sub

''' 

''' Initializes a new instance of the  class
''' with the specified error message.
''' 

''' The message that describes the error.
 Public Sub New(ByVal message As String)
 MyBase.New(message)
 End Sub

''' 

''' Initializes a new instance of the  class
''' with the specified error message and a reference to the inner
''' exception that is the cause of this exception.
''' 

 ''' The message that describes the error.
''' The exception that is the cause of the
 ' '' current exception, or a null reference if no inner exception is 
''' specified
 Public Sub New(ByVal message As String, ByVal innerException As System.Exception)
 MyBase.New(message, innerException)
 End Sub 

 'Constructor required for serialization
  _
 Protected Sub New(ByVal info As SerializationInfo, ByVal context As StreamingContext)
 MyBase.New(info , context)
 End Sub

End Class

Ah, after posting the above, I realized that I may have completely misunderstood your question. I (and other Answer) I think you are asking for an example of how to implement a user-defined exception class. When you do something like this in your own project, it looks like you are just asking for some examples… that’s too complicated.

< p>Most of the time, you don’t want to do this. The only time you should throw a custom exception is when you are writing a reusable code library (such as a .DLL file), and you want the client code to behave based on the specific exception thrown Different reactions. So, in my case, I throw a DwmException from the class library because the client application may want to catch the exception and disable some peculiar UI features when the DWM combination is not enabled on the user’s computer. Normally, I only throw the standard NotSupportedException, but in this case, I want the client to be able to distinguish between exceptions that they can handle and exceptions that they can’t or shouldn’t handle.

In a standard application, all code is self-contained (i.e., when you are not creating a reusable code base), you basically should not create/throw custom exceptions. Instead, throw a standard .Following the above rules, if you need to throw a custom exception to affect the response of the client code, then this indicates that you have used “flow control” exceptions within the application (because the producer and the consumer are in the same ), strongly discouraged.