ExceptionHandlingClauseOptions Enumeration

Definition

public enum class ExceptionHandlingClauseOptions

[System.Flags]
public enum ExceptionHandlingClauseOptions

[System.Flags]
[System.Runtime.InteropServices.ComVisible(true)]
public enum ExceptionHandlingClauseOptions

[<System.Flags>]
type ExceptionHandlingClauseOptions = 

[<System.Flags>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type ExceptionHandlingClauseOptions = 

Public Enum ExceptionHandlingClauseOptions

Vererbung

Object

ValueType

Enum

ExceptionHandlingClauseOptions

Attribute

FlagsAttribute ComVisibleAttribute

Felder

Beispiele

Das folgende Codebeispiel definiert eine Testmethode mit dem Namen MethodBodyExampleund zeigt die lokalen Variableninformationen und Ausnahmebehandlungsklauseln an. Die MethodBase.GetMethodBody Methode wird verwendet, um ein MethodBody Objekt für die Testmethode abzurufen. Die ExceptionHandlingClauses Eigenschaft wird verwendet, um eine Liste von ExceptionHandlingClause Objekten abzurufen und deren Eigenschaften anzuzeigen.

Dieser Code ist Teil eines größeren Beispiels, das für die MethodBody Klasse bereitgestellt wird.

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();
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 == null)
            {
                throw new ArgumentNullException("The argument cannot be null.");
            }
            if (arg.GetType() == typeof(string))
            {
                throw new ArgumentException("The argument cannot be a string.");
            }
        }

        // This filter clause selects only exceptions that derive
        // from the ArgumentException class.
        // Other exceptions, including ArgumentException itself,
        // are not handled by this filter clause.
        catch (ArgumentException ex) when (ex.GetType().IsSubclassOf(typeof(ArgumentException)))
        {
            Console.WriteLine("Filter clause caught: {0}", ex.GetType());
        }

        // 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

//
//Filter
//      Filter Offset: 71
//      Handler Length: 23
//      Handler Offset: 116
//      Try Block Length: 61
//      Try Block Offset: 10
//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

Um die Ausnahmebehandlungsklauseln in einer Methode zu untersuchen, rufen Sie ein MethodInfo Objekt ab, und rufen Sie die GetMethodBody Methode auf, um den Methodentext abzurufen. Verwenden Sie die ExceptionHandlingClauses Eigenschaft, um eine Liste von ExceptionHandlingClause Objekten abzurufen.

Weitere Informationen

• MethodBody
• ExceptionHandlingClause