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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)

public virtual string HelpLink { get; set; }

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. 
using System;

namespace NDP_UE_CS
{
    // Derive an exception; the constructor sets the HelpLink and  
    // Source properties. 
    class LogTableOverflowException : Exception
    {
        const string overflowMessage = "The log table has overflowed.";

        public LogTableOverflowException( 
            string auxMessage, Exception inner ) :
                base( String.Format( "{0} - {1}", 
                    overflowMessage, auxMessage ), inner )
        {
            this.HelpLink = "http://msdn.microsoft.com";
            this.Source = "Exception_Class_Samples";
        }
    }

    class LogTable
    {
        public LogTable( int numElements )
        {
            logArea = new string[ numElements ];
            elemInUse = 0;
        }

        protected string[ ] logArea;
        protected int       elemInUse;

        // The AddRecord method throws a derived exception if  
        // the array bounds exception is caught. 
        public     int       AddRecord( string newRecord )
        {
            try
            {
                logArea[ elemInUse ] = newRecord;
                return elemInUse++;
            }
            catch( Exception e )
            {
                throw new LogTableOverflowException( 
                    String.Format( "Record \"{0}\" was not logged.", 
                        newRecord ), e );
            }
        }
    }

    class OverflowDemo 
    {
        // Create a log table and force an overflow. 
        public static void Main() 
        {
            LogTable log = new LogTable( 4 );

            Console.WriteLine( 
                "This example of \n   Exception.Message, \n" +
                "   Exception.HelpLink, \n   Exception.Source, \n" +
                "   Exception.StackTrace, and \n   Exception." +
                "TargetSite \ngenerates the following output." );

            try
            {
                for( int count = 1; ; count++ )
                {
                    log.AddRecord( 
                        String.Format( 
                            "Log record number {0}", count ) );
                }
            }
            catch( Exception ex )
            {
                Console.WriteLine( "\nMessage ---\n{0}", ex.Message );
                Console.WriteLine( 
                    "\nHelpLink ---\n{0}", ex.HelpLink );
                Console.WriteLine( "\nSource ---\n{0}", ex.Source );
                Console.WriteLine( 
                    "\nStackTrace ---\n{0}", ex.StackTrace );
                Console.WriteLine( 
                    "\nTargetSite ---\n{0}", ex.TargetSite );
            }
        }
    }
}

/*
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_CS.LogTable.AddRecord(String newRecord)
   at NDP_UE_CS.OverflowDemo.Main()

TargetSite ---
Int32 AddRecord(System.String)
*/

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone 8, Silverlight 8.1

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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