Gets a list that includes all the exception-handling clauses in the method body.
Namespace:
System.Reflection
Assembly:
mscorlib (in mscorlib.dll)
Visual Basic (Declaration)
Public ReadOnly Property ExceptionHandlingClauses As IList(Of ExceptionHandlingClause)
Dim instance As MethodBody
Dim value As IList(Of ExceptionHandlingClause)
value = instance.ExceptionHandlingClauses
public IList<ExceptionHandlingClause> ExceptionHandlingClauses { get; }
public:
property IList<ExceptionHandlingClause^>^ ExceptionHandlingClauses {
IList<ExceptionHandlingClause^>^ get ();
}
public function get ExceptionHandlingClauses () : IList<ExceptionHandlingClause>
The list includes all clauses from all try blocks in the method body. Each ExceptionHandlingClause object contains information that identifies the try block with which it is associated.
The following code example defines a test method named MethodBodyExample and displays information about its exception-handling clauses. The MethodBase..::.GetMethodBody method is used to obtain a MethodBody object for the test method. The ExceptionHandlingClauses property is used to obtain a list of ExceptionHandlingClause objects.
Note: |
|---|
Not all computer languages can generate ExceptionHandlingClauseOptions..::.Filter clauses. The Visual Basic example shows a filter clause, using a Visual Basic When expression, which is omitted from the examples for other languages. |
This code example is part of a larger example provided for the MethodBody class.
Imports System
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 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
...
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: 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
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);
...
// 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);
}
...
}
// 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
...
//
//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
#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);
...
// 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);
}
...
// 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.";
}
}
...
//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
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
.NET Framework
Supported in: 3.5, 3.0, 2.0
Reference