ExceptionHandlingClause Klasse

Definition

Stellt eine Klausel in einem strukturierten Ausnahmebehandlungsblock dar.Represents a clause in a structured exception-handling block.

public ref class ExceptionHandlingClause
[System.Runtime.InteropServices.ComVisible(true)]
public class ExceptionHandlingClause
type ExceptionHandlingClause = class
Public Class ExceptionHandlingClause
Vererbung
ExceptionHandlingClause
Attribute

Beispiele

Im folgenden Codebeispiel wird eine Testmethode mit MethodBodyExampledem Namen definiert, und die Informationen zu lokalen Variablen und die Ausnahmebehandlung werden angezeigt.The following code example defines a test method named MethodBodyExample, and displays its local variable information and exception-handling clauses. Die MethodBase.GetMethodBody -Methode wird verwendet, um MethodBody ein-Objekt für die Testmethode abzurufen.The MethodBase.GetMethodBody method is used to obtain a MethodBody object for the test method. Die ExceptionHandlingClauses -Eigenschaft wird zum Abrufen einer Liste von ExceptionHandlingClause -Objekten und zum Anzeigen ihrer Eigenschaften verwendet.The ExceptionHandlingClauses property is used to obtain a list of ExceptionHandlingClause objects and display their properties.

Sie können "Ildasm. exe" verwenden, um die MSIL für das kompilierte Codebeispiel zu untersuchen, um zu sehen, wie die Offsets und Längen berechnet werden.You can use Ildasm.exe to examine the MSIL for the compiled code example, to see how the offsets and lengths are calculated.

Hinweis

Nicht alle Computersprachen können Klauseln ExceptionHandlingClauseOptions.Filter generieren.Not all computer languages can generate ExceptionHandlingClauseOptions.Filter clauses. Das Visual Basic Beispiel zeigt eine Filter Klausel mithilfe eines Visual Basic When Ausdrucks, der in den Beispielen für andere Sprachen ausgelassen wird.The Visual Basic example shows a filter clause, using a Visual Basic When expression, which is omitted from the examples for other languages.

Dieser Code ist Teil eines größeren Beispiels, das sich im MethodBody Thema zur-Klasse befindet.This code is part of a larger example located in the MethodBody class topic.

#using <System.dll>

using namespace System;
using namespace System::Reflection;

public ref class Example
{
    // The Main method contains code to analyze this method, using
    // the properties and methods of the MethodBody class.
public:
    void MethodBodyExample(Object^ arg)
    {
        // Define some local variables. In addition to these variables,
        // the local variable list includes the variables scoped to 
        // the catch clauses.
        int var1 = 42;
        String^ var2 = "Forty-two";

        try
        {
            // Depending on the input value, throw an ArgumentException or 
            // an ArgumentNullException to test the Catch clauses.
            if (arg == nullptr)
            {
                throw gcnew ArgumentNullException("The argument cannot " +
                    "be null.");
            }
            if (arg->GetType() == String::typeid)
            {
                throw gcnew ArgumentException("The argument cannot " + 
                    "be a string.");
            }        
        }

        // There is no Filter clause in this code example. See the Visual 
        // Basic code for an example of a Filter clause.

        // This catch clause handles the ArgumentException class, and
        // any other class derived from Exception.
        catch (ArgumentException^ ex)
        {
            Console::WriteLine("Ordinary exception-handling clause caught:" +
                " {0}", ex->GetType());
        }        
        finally
        {
            var1 = 3033;
            var2 = "Another string.";
        }
    }
};

int main()
{ 
    // Get method body information.
    MethodInfo^ mi = 
        Example::typeid->GetMethod("MethodBodyExample");

    MethodBody^ mb = mi->GetMethodBody();
    Console::WriteLine("\r\nMethod: {0}", mi);

    // Display the general information included in the 
    // MethodBody object.
    Console::WriteLine("    Local variables are initialized: {0}", 
        mb->InitLocals);
    Console::WriteLine("    Maximum number of items on the operand " +
        "stack: {0}", mb->MaxStackSize);
using System;
using System.Reflection;

public class Example
{
    public static void Main()
    {
        // Get method body information.
        MethodInfo mi = typeof(Example).GetMethod("MethodBodyExample");
        MethodBody mb = mi.GetMethodBody();
        Console.WriteLine("\r\nMethod: {0}", mi);

        // Display the general information included in the 
        // MethodBody object.
        Console.WriteLine("    Local variables are initialized: {0}", 
            mb.InitLocals);
        Console.WriteLine("    Maximum number of items on the operand stack: {0}", 
            mb.MaxStackSize);
Imports System.Reflection

Public Class Example

    Public Shared Sub Main()

        ' Demonstrate the effect of the Visual Basic When keyword, which
        ' generates a Filter clause in the Try block.
        Dim e As New Example()
        Console.WriteLine()
        e.MethodBodyExample("String argument")
        e.MethodBodyExample(Nothing)

        ' Get method body information.
        Dim mi As MethodInfo = _
            GetType(Example).GetMethod("MethodBodyExample")
        Dim mb As MethodBody = mi.GetMethodBody()
        Console.WriteLine(vbCrLf & "Method: {0}", mi)

        ' Display the general information included in the 
        ' MethodBody object.
        Console.WriteLine("    Local variables are initialized: {0}", _
            mb.InitLocals)
        Console.WriteLine("    Maximum number of items on the operand stack: {0}", _
            mb.MaxStackSize)

// Display exception handling clauses.
Console::WriteLine();
for each(ExceptionHandlingClause^ exhc in mb->ExceptionHandlingClauses)
{
    Console::WriteLine(exhc->Flags.ToString());

    // The FilterOffset property is meaningful only for Filter
    // clauses. The CatchType property is not meaningful for 
    // Filter or Finally clauses. 
    switch(exhc->Flags)
    {
    case ExceptionHandlingClauseOptions::Filter:
        Console::WriteLine("        Filter Offset: {0}", 
            exhc->FilterOffset);
        break;
    case ExceptionHandlingClauseOptions::Finally:
        break;
    default:
        Console::WriteLine("    Type of exception: {0}", 
            exhc->CatchType);
        break;
    }

    Console::WriteLine("       Handler Length: {0}",
        exhc->HandlerLength);
    Console::WriteLine("       Handler Offset: {0}", 
        exhc->HandlerOffset);
    Console::WriteLine("     Try Block Length: {0}", exhc->TryLength);
    Console::WriteLine("     Try Block Offset: {0}", exhc->TryOffset);
}

// Display exception handling clauses.
Console.WriteLine();
foreach (ExceptionHandlingClause ehc in mb.ExceptionHandlingClauses)
{
    Console.WriteLine(ehc.Flags.ToString());

    // The FilterOffset property is meaningful only for Filter
    // clauses. The CatchType property is not meaningful for 
    // Filter or Finally clauses. 
    switch (ehc.Flags)
    {
        case ExceptionHandlingClauseOptions.Filter:
            Console.WriteLine("        Filter Offset: {0}", 
                ehc.FilterOffset);
            break;
        case ExceptionHandlingClauseOptions.Finally:
            break;
        default:
            Console.WriteLine("    Type of exception: {0}", 
                ehc.CatchType);
            break;
    }

    Console.WriteLine("       Handler Length: {0}", ehc.HandlerLength);
    Console.WriteLine("       Handler Offset: {0}", ehc.HandlerOffset);
    Console.WriteLine("     Try Block Length: {0}", ehc.TryLength);
    Console.WriteLine("     Try Block Offset: {0}", ehc.TryOffset);
}

' Display exception handling clauses.
Console.WriteLine()
For Each ehc As ExceptionHandlingClause In mb.ExceptionHandlingClauses
    Console.WriteLine(ehc.Flags.ToString())

    ' The FilterOffset property is meaningful only for Filter
    ' clauses. The CatchType property is not meaningful for 
    ' Filter or Finally clauses. 
    Select Case ehc.Flags
        Case ExceptionHandlingClauseOptions.Filter
            Console.WriteLine("        Filter Offset: {0}", _
                ehc.FilterOffset)
        Case ExceptionHandlingClauseOptions.Finally
        Case Else
            Console.WriteLine("    Type of exception: {0}", _
                ehc.CatchType)
    End Select

    Console.WriteLine("       Handler Length: {0}", ehc.HandlerLength)
    Console.WriteLine("       Handler Offset: {0}", ehc.HandlerOffset)
    Console.WriteLine("     Try Block Length: {0}", ehc.TryLength)
    Console.WriteLine("     Try Block Offset: {0}", ehc.TryOffset)
Next
    // The Main method contains code to analyze this method, using
    // the properties and methods of the MethodBody class.
public:
    void MethodBodyExample(Object^ arg)
    {
        // Define some local variables. In addition to these variables,
        // the local variable list includes the variables scoped to 
        // the catch clauses.
        int var1 = 42;
        String^ var2 = "Forty-two";

        try
        {
            // Depending on the input value, throw an ArgumentException or 
            // an ArgumentNullException to test the Catch clauses.
            if (arg == nullptr)
            {
                throw gcnew ArgumentNullException("The argument cannot " +
                    "be null.");
            }
            if (arg->GetType() == String::typeid)
            {
                throw gcnew ArgumentException("The argument cannot " + 
                    "be a string.");
            }        
        }

        // There is no Filter clause in this code example. See the Visual 
        // Basic code for an example of a Filter clause.

        // This catch clause handles the ArgumentException class, and
        // any other class derived from Exception.
        catch (ArgumentException^ ex)
        {
            Console::WriteLine("Ordinary exception-handling clause caught:" +
                " {0}", ex->GetType());
        }        
        finally
        {
            var1 = 3033;
            var2 = "Another string.";
        }
    }
    }

    // The Main method contains code to analyze this method, using
    // the properties and methods of the MethodBody class.
    public void MethodBodyExample(object arg)
    {
        // Define some local variables. In addition to these variables,
        // the local variable list includes the variables scoped to 
        // the catch clauses.
        int var1 = 42;
        string var2 = "Forty-two";

        try
        {
            // Depending on the input value, throw an ArgumentException or 
            // an ArgumentNullException to test the Catch clauses.
            if (arg == null)
            {
                throw new ArgumentNullException("The argument cannot be null.");
            }
            if (arg.GetType() == typeof(string))
            {
                throw new ArgumentException("The argument cannot be a string.");
            }        
        }

        // There is no Filter clause in this code example. See the Visual 
        // Basic code for an example of a Filter clause.

        // This catch clause handles the ArgumentException class, and
        // any other class derived from Exception.
        catch(Exception ex)
        {
            Console.WriteLine("Ordinary exception-handling clause caught: {0}", 
                ex.GetType());
        }        
        finally
        {
            var1 = 3033;
            var2 = "Another string.";
        }
    }
}

// This code example produces output similar to the following:
//
//Method: Void MethodBodyExample(System.Object)
//    Local variables are initialized: True
//    Maximum number of items on the operand stack: 2
    End Sub

    ' This test method is executed at the beginning of Main, to show
    ' how the Filter clause works. The Filter clause is generated by 
    ' a Visual Basic When expression. If arg is Nothing, this method
    ' throws ArgumentNullException, which is caught by the filter
    ' clause. If arg is a string, the method throws ArgumentException,
    ' which does not match the filter clause.
    '
    ' Sub Main also contains code to analyze this method, using 
    ' the properties and methods of the MethodBody class.
    Public Sub MethodBodyExample(ByVal arg As Object)

        ' Define some local variables. In addition to these variables,
        ' the local variable list includes the variables scoped to 
        ' the catch clauses.
        Dim var1 As Integer = 42
        Dim var2 As String = "Forty-two"

        Try
            ' Depending on the input value, throw an ArgumentException or 
            ' an ArgumentNullException to test the Catch clauses.
            '
            If arg Is Nothing Then
                Throw New ArgumentNullException("The argument cannot be Nothing.")
            End If
            If arg.GetType() Is GetType(String) Then
                Throw New ArgumentException("The argument cannot be a string.")
            End If
        
        ' The When expression makes this a filter clause. The expression 
        ' selects only exceptions that derive from the ArgumentException
        ' class. Other exceptions, including ArgumentException itself, 
        ' are not handled by this filter clause.
        Catch ex As ArgumentException _
            When ex.GetType().IsSubclassOf(GetType(ArgumentException))

            Console.WriteLine("Filter clause caught: {0}", ex.GetType())
        
        ' This catch clause handles the ArgumentException class, and
        ' any other class derived from Exception.
        Catch ex As Exception
            Console.WriteLine("Ordinary exception-handling clause caught: {0}", _
                ex.GetType())

        Finally
            var1 = 3033
            var2 = "Another string."
        End Try
    End Sub
End Class

' This code example produces output similar to the following:
'
'Ordinary exception-handling clause caught: System.ArgumentException
'Filter clause caught: System.ArgumentNullException
'
'Method: Void MethodBodyExample(System.Object)
'    Local variables are initialized: True
'    Maximum number of items on the operand stack: 3
//Clause
//    Type of exception: System.ArgumentException
//       Handler Length: 29
//       Handler Offset: 78
//     Try Block Length: 65
//     Try Block Offset: 13
//Finally
//       Handler Length: 13
//       Handler Offset: 113
//     Try Block Length: 100
//     Try Block Offset: 13
//
//Clause
//    Type of exception: System.Exception
//       Handler Length: 21
//       Handler Offset: 70
//     Try Block Length: 61
//     Try Block Offset: 9
//Finally
//       Handler Length: 14
//       Handler Offset: 94
//     Try Block Length: 85
//     Try Block Offset: 9
'
'Filter
'        Filter Offset: 0
'       Handler Length: 19
'       Handler Offset: 99
'     Try Block Length: 45
'     Try Block Offset: 9
'Clause
'    Type of exception: System.Exception
'       Handler Length: 25
'       Handler Offset: 118
'     Try Block Length: 45
'     Try Block Offset: 9
'Finally
'       Handler Length: 13
'       Handler Offset: 153
'     Try Block Length: 144
'     Try Block Offset: 9

Hinweise

Die ExceptionHandlingClause -Klasse stellt Informationen zu den-Klauseln tryin einer... catch...finallyThe ExceptionHandlingClause class provides information about the clauses in a trycatchfinally Block (Try... Catch...Finallyblock (TryCatchFinally in Visual Basic).in Visual Basic). Zum Abrufen einer Liste der Klauseln zur Ausnahmebehandlung in einer Methode rufen Sie eine MethodInfo ab, die die Methode darstellt.To get a list of exception-handling clauses in a method, obtain a MethodInfo that represents the method. Verwenden Sie GetMethodBody die-Methode, MethodBody um ein-Objekt abzurufen, ExceptionHandlingClauses und verwenden Sie dann die-Eigenschaft, um die Liste der Klauseln abzurufen.Use the GetMethodBody method to obtain a MethodBody object, and then use the ExceptionHandlingClauses property to get the list of clauses.

Hinweis

Die Verwendung von Klauseln für die Ausnahmebehandlung erfordert ein umfassendes Verständnis von Metadaten und MSIL-Anweisungs Formaten (Microsoft Intermediate Language).Working with exception-handling clauses requires a thorough understanding of metadata and Microsoft intermediate language (MSIL) instruction formats. Informationen finden Sie in der Common Language Infrastructure-Dokumentation (CLI), insbesondere "Partition II: Metadatendefinition und Semantik) und „Partition III: CIL Instruction Set“ (Partition III: CIL-Anweisungen).Information can be found in the Common Language Infrastructure (CLI) documentation, especially "Partition II: Metadata Definition and Semantics" and "Partition III: CIL Instruction Set". Die Dokumentation ist online verfügbar. Sie finden sie unter ECMA C# and Common Language Infrastructure Standards (Standards von ECMA C# und Common Language Infrastructure) auf MSDN und Standard ECMA-335 - Common Language Infrastructure (CLI) (Standard ECMA-335 – Common Language Infrastructure (CLI)) auf der Ecma International-Website.The documentation is available online; see ECMA C# and Common Language Infrastructure Standards on MSDN and Standard ECMA-335 - Common Language Infrastructure (CLI) on the Ecma International Web site.

Konstruktoren

ExceptionHandlingClause()

Initialisiert eine neue Instanz der ExceptionHandlingClause-Klasse.Initializes a new instance of the ExceptionHandlingClause class.

Eigenschaften

CatchType

Ruft den Typ der von dieser Klausel behandelten Ausnahme ab.Gets the type of exception handled by this clause.

FilterOffset

Ruft den Offset des vom Benutzer angegebenen Filtercodes innerhalb des Methodentexts ab (in Byte).Gets the offset within the method body, in bytes, of the user-supplied filter code.

Flags

Ruft einen Wert ab, der angibt, ob diese Klausel zur Ausnahmebehandlung eine finally-Klausel, eine nach Typ gefilterte Klausel oder eine nach Benutzer gefilterte Klausel ist.Gets a value indicating whether this exception-handling clause is a finally clause, a type-filtered clause, or a user-filtered clause.

HandlerLength

Ruft die Länge des Texts dieser Klausel zur Ausnahmebehandlung ab (in Byte).Gets the length, in bytes, of the body of this exception-handling clause.

HandlerOffset

Ruft den Offset dieser Klausel zur Ausnahmebehandlung innerhalb des Methodentexts ab (in Byte).Gets the offset within the method body, in bytes, of this exception-handling clause.

TryLength

Die Gesamtlänge des try-Blocks, der diese Klausel zur Ausnahmebehandlung einschließt (in Byte).The total length, in bytes, of the try block that includes this exception-handling clause.

TryOffset

Der Offset des diese Klausel zur Ausnahmebehandlung einschließenden try-Blocks innerhalb der Methode (in Byte).The offset within the method, in bytes, of the try block that includes this exception-handling clause.

Methoden

Equals(Object)

Ermittelt, ob das angegebene Objekt und das aktuelle Objekt gleich sind.Determines whether the specified object is equal to the current object.

(Geerbt von Object)
GetHashCode()

Dient als die Standard-HashfunktionServes as the default hash function.

(Geerbt von Object)
GetType()

Ruft den Type der aktuellen Instanz ab.Gets the Type of the current instance.

(Geerbt von Object)
MemberwiseClone()

Erstellt eine flache Kopie des aktuellen Object.Creates a shallow copy of the current Object.

(Geerbt von Object)
ToString()

Eine Zeichenfolgendarstellung der Klausel zur Ausnahmebehandlung.A string representation of the exception-handling clause.

Gilt für:

Siehe auch