Exception.Message 屬性
定義
重要
部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。
取得描述目前例外狀況的訊息。
public:
virtual property System::String ^ Message { System::String ^ get(); };public virtual string Message { get; }member this.Message : stringPublic Overridable ReadOnly Property Message As String屬性值
說明例外狀況原因的錯誤訊息，或空字串 ("")。
實作
範例
下列程式代碼範例會擲回並攔截 Exception 例外狀況，並使用 屬性顯示例外狀況的文字訊息 Message 。
// Example for the Exception::HelpLink, Exception::Source,
// Exception::StackTrace, and Exception::TargetSite properties.
using namespace System;
namespace NDP_UE_CPP
{
// Derive an exception; the constructor sets the HelpLink and
// Source properties.
public ref class LogTableOverflowException: public Exception
{
private:
static String^ overflowMessage = "The log table has overflowed.";
public:
LogTableOverflowException( String^ auxMessage, Exception^ inner )
: Exception( String::Format( "{0} - {1}", overflowMessage, auxMessage ), inner )
{
this->HelpLink = "https://learn.microsoft.com";
this->Source = "Exception_Class_Samples";
}
};
public ref class LogTable
{
public:
LogTable( int numElements )
{
logArea = gcnew array<String^>(numElements);
elemInUse = 0;
}
protected:
array<String^>^logArea;
int elemInUse;
public:
// The AddRecord method throws a derived exception if
// the array bounds exception is caught.
int AddRecord( String^ newRecord )
{
try
{
logArea[ elemInUse ] = newRecord;
return elemInUse++;
}
catch ( Exception^ ex )
{
throw gcnew LogTableOverflowException( String::Format( "Record \"{0}\" was not logged.", newRecord ),ex );
}
}
};
// Create a log table and force an overflow.
void ForceOverflow()
{
LogTable^ log = gcnew LogTable( 4 );
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->ToString() );
}
}
}
int main()
{
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." );
NDP_UE_CPP::ForceOverflow();
}
/*
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_CPP.LogTable.AddRecord(String newRecord)
at NDP_UE_CPP.ForceOverflow()
TargetSite ---
Int32 AddRecord(System.String)
*/
// 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)
備註
錯誤訊息是以處理例外狀況的開發人員為目標。 屬性的 Message 文字應該完全描述錯誤，而且可能的話，也應該說明如何更正錯誤。 最上層的例外狀況處理程式可能會向用戶顯示訊息，因此您應該確定其語法正確，而且訊息的每個句子都會以句號結束。 請勿使用問號或驚嘆號。 如果您的應用程式使用本地化的例外狀況訊息，您應該確定它們已正確翻譯。
重要
若未檢查適當的許可權，請勿在例外狀況訊息中揭露敏感性資訊。
屬性的值 Message 會包含在 所 ToString傳回的資訊中。 Message只有在建立 Exception時，才會設定 屬性。 如果未將訊息提供給目前實例的建構函式，則系統會提供使用目前系統文化特性格式化的預設訊息。
給繼承者的注意事項
屬性 Message 會在需要控制訊息內容或格式的類別中覆寫。 應用程式程式代碼通常需要顯示已攔截之例外狀況的相關信息時，通常會存取這個屬性。
錯誤訊息應當地語系化。
