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Exception.HelpLink Property

Gets or sets a link to the help file associated with this exception.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

'Declaration
Public Overridable Property HelpLink As String
'Usage
Dim instance As Exception 
Dim value As String 

value = instance.HelpLink

instance.HelpLink = value

Property Value

Type: System.String
The Uniform Resource Name (URN) or Uniform Resource Locator (URL).

Implements

_Exception.HelpLink

The return value, which represents a help file, is a URN or URL. For example, the HelpLink value could be:

"file:///C:/Applications/Bazzal/help.html#ErrorNum42"

The following code example throws an Exception that sets the HelpLink property in its constructor and then catches the exception and displays HelpLink.

' Example for the Exception.HelpLink, Exception.Source, 
' Exception.StackTrace, and Exception.TargetSite properties. 
Imports System
Imports Microsoft.VisualBasic

Namespace NDP_UE_VB

    ' Derive an exception; the constructor sets the HelpLink and  
    ' Source properties. 
    Class LogTableOverflowException
        Inherits Exception

        Private Const overflowMessage As String = _
            "The log table has overflowed." 

        Public Sub New( auxMessage As String, inner As Exception )
            MyBase.New( String.Format( "{0} - {1}", _
                overflowMessage, auxMessage ), inner )

            Me.HelpLink = "http://msdn.microsoft.com" 
            Me.Source = "Exception_Class_Samples" 

        End Sub ' New 
    End Class ' LogTableOverflowException

    Class LogTable

        Public Sub New(numElements As Integer)
            logArea = New String(numElements) {}
            elemInUse = 0
        End Sub ' New 

        Protected logArea() As String 
        Protected elemInUse As Integer 

        ' The AddRecord method throws a derived exception if  
        ' the array bounds exception is caught. 
        Public Function AddRecord( newRecord As String ) As Integer 

            Try 
                Dim curElement as Integer = elemInUse
                logArea( elemInUse ) = newRecord
                elemInUse += 1
                Return curElement

            Catch ex As Exception
                Throw New LogTableOverflowException( _
                    String.Format( "Record ""{0}"" was not logged.", _
                        newRecord ), ex )
            End Try 
        End Function ' AddRecord
    End Class ' LogTable

    Module OverflowDemo

        ' Create a log table and force an overflow. 
        Sub Main( )
            Dim log As New LogTable( 4 )

            Console.WriteLine( "This example of " & vbCrLf & _
                "   Exception.Message, " & vbCrLf & _
                "   Exception.HelpLink, " & vbCrLf & _
                "   Exception.Source, " & vbCrLf & _
                "   Exception.StackTrace, and " & vbCrLf & _
                "   Exception.TargetSite " & vbCrLf & _
                "generates the following output." )

            Try 
                Dim count As Integer = 0

                Do
                    log.AddRecord( _
                        String.Format( "Log record number {0}", count ) )
                    count += 1
                Loop 

            Catch ex As Exception
                Console.WriteLine( vbCrLf & _
                    "Message ---" & vbCrLf & ex.Message )
                Console.WriteLine( vbCrLf & _
                    "HelpLink ---" & vbCrLf & ex.HelpLink )
                Console.WriteLine( vbCrLf & _
                    "Source ---" & vbCrLf & ex.Source )
                Console.WriteLine( vbCrLf & _
                    "StackTrace ---" & vbCrLf & ex.StackTrace )
                Console.WriteLine( vbCrLf & "TargetSite ---" & _
                    vbCrLf & ex.TargetSite.ToString( ) )
            End Try 
        End Sub ' Main

    End Module ' OverflowDemo
End Namespace ' NDP_UE_VB

' This example of 
'    Exception.Message, 
'    Exception.HelpLink, 
'    Exception.Source, 
'    Exception.StackTrace, and 
'    Exception.TargetSite 
' generates the following output. 
'  
' Message --- 
' The log table has overflowed. - Record "Log record number 5" was not logged. 
'  
' HelpLink --- 
' http://msdn.microsoft.com 
'  
' Source --- 
' Exception_Class_Samples 
'  
' StackTrace --- 
'    at NDP_UE_VB.LogTable.AddRecord(String newRecord) 
'    at NDP_UE_VB.OverflowDemo.Main() 
'  
' TargetSite --- 
' Int32 AddRecord(System.String)

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0
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