Exception.Message Property

public:
 virtual property System::String ^ Message { System::String ^ get(); };

public virtual string Message { get; }

member this.Message : string

Public Overridable ReadOnly Property Message As String

Property Value

The error message that explains the reason for the exception, or an empty string ("").

Implements

Examples

The following code example throws and then catches an Exception exception and displays the exception's text message using the Message property.

// 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 = "https://learn.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 ---
https://learn.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)
*/

// Example for the Exception.HelpLink, Exception.Source,
// Exception.StackTrace, and Exception.TargetSite properties.
open System
 
let overflowMessage = "The log table has overflowed."

// Derive an exception; the constructor sets the HelpLink and
// Source properties.
type LogTableOverflowException(auxMessage, inner) as this =
 inherit Exception($"%s{overflowMessage} - %s{auxMessage}", inner)

 do
 this.HelpLink <- "https://learn.microsoft.com"
 this.Source <- "Exception_Class_Samples"

type LogTable(numElements) =
 let logArea = Array.zeroCreate<string> numElements
 let mutable elemInUse = 0

 // The AddRecord method throws a derived exception if
 // the array bounds exception is caught.
 member this.AddRecord(newRecord) =
 try
 logArea[elemInUse] <- newRecord
 elemInUse <- elemInUse + 1
 elemInUse - 1 
 with e ->
 raise (LogTableOverflowException($"Record \"{newRecord}\" was not logged.", e) )

// Create a log table and force an overflow.
let log = LogTable 4 

printfn
 """This example of
 Exception.Message, 
 Exception.HelpLink, 
 Exception.Source, 
 Exception.StackTrace, and
 Exception.TargetSite 
 generates the following output."""

try
 for count = 1 to 1000000 do
 log.AddRecord $"Log record number {count}"
 |> ignore
with ex ->
 printfn $"\nMessage ---\n{ex.Message}"
 printfn $"\nHelpLink ---\n{ex.HelpLink}"
 printfn $"\nSource ---\n{ex.Source}"
 printfn $"\nStackTrace ---\n{ex.StackTrace}"
 printfn $"\nTargetSite ---\n{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 ---
// https://learn.microsoft.com

// Source ---
// Exception_Class_Samples

// StackTrace ---
// at NDP_UE_FS.LogTable.AddRecord(String newRecord)
// at <StartupCode$fs>.$NDP_UE_FS.main@()

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

' Example for the Exception.HelpLink, Exception.Source,
' Exception.StackTrace, and Exception.TargetSite properties.
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 = "https://learn.microsoft.com"
 Me.Source = "Exception_Class_Samples"

 End Sub
 End Class

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

 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

 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 ---
' https://learn.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)

Remarks

Error messages target the developer who is handling the exception. The text of the Message property should completely describe the error and, when possible, should also explain how to correct the error. Top-level exception handlers may display the message to end-users, so you should ensure that it is grammatically correct and that each sentence of the message ends with a period. Do not use question marks or exclamation points. If your application uses localized exception messages, you should ensure that they are accurately translated.

The value of the Message property is included in the information returned by ToString. The Message property is set only when creating an Exception. If no message was supplied to the constructor for the current instance, the system supplies a default message that is formatted using the current system culture.

Notes to Inheritors

The Message property is overridden in classes that require control over message content or format. Application code typically accesses this property when it needs to display information about an exception that has been caught.

The error message should be localized.