MethodBody.ExceptionHandlingClauses 属性

定义

命名空间:

System.Reflection

程序集:

netstandard.dll, System.Runtime.dll

Source:

MethodBody.cs

获取在方法主体中包含所有异常处理的子句的列表。

public virtual System.Collections.Generic.IList<System.Reflection.ExceptionHandlingClause> ExceptionHandlingClauses { get; }

属性值

IList<ExceptionHandlingClause>

ExceptionHandlingClause 对象的 IList<T> 表示方法主体中异常处理的子句。

示例

下面的代码示例定义名为 MethodBodyExample 的测试方法，并显示有关其异常处理子句的信息。 方法 MethodBase.GetMethodBody 用于获取 MethodBody 测试方法的 对象。 属性 ExceptionHandlingClauses 用于获取对象的列表 ExceptionHandlingClause 。

此代码示例是为 MethodBody 类提供的一个更大示例的一部分。

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.");
            }
        }

        // 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

//
//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

注解

该列表包括方法主体中所有 try 块中的所有子句。 每个 ExceptionHandlingClause 对象都包含标识与其关联的 try 块的信息。

备注

使用异常处理子句需要全面了解元数据和 MSIL 指令格式。 可以在 公共语言基础结构 (CLI) 文档中找到信息，尤其是“分区 II：元数据定义和语义”。

适用于

另请参阅

• ExceptionHandlingClause
• ExceptionHandlingClauseOptions