MissingMemberException 类

定义

命名空间:

System

程序集:

System.Runtime.dll

Source:

MissingMemberException.cs

当尝试动态访问不存在或未声明为公共的类成员时引发的异常。 如果类库中的成员已删除或重命名，请重新编译引用该库的任何程序集。

public ref class MissingMemberException : MemberAccessException

public class MissingMemberException : MemberAccessException

type MissingMemberException = class
    inherit MemberAccessException

Public Class MissingMemberException
Inherits MemberAccessException

继承

Object

Exception

SystemException

MemberAccessException

MissingMemberException

派生

System.MissingFieldException

System.MissingMethodException

示例

此示例演示了如果尝试使用反射来调用不存在的方法并访问不存在的字段，会发生什么情况。 应用程序通过捕获 MissingMethodException、MissingFieldException和 MissingMemberException来恢复。

using namespace System;
using namespace System::Reflection;

ref class App
{
};

int main()
{
    try
    {
        // Attempt to call a static DoSomething method defined in the App class.
        // However, because the App class does not define this method,
        // a MissingMethodException is thrown.
        App::typeid->InvokeMember("DoSomething", BindingFlags::Static |
            BindingFlags::InvokeMethod, nullptr, nullptr, nullptr);
    }
    catch (MissingMethodException^ ex)
    {
        // Show the user that the DoSomething method cannot be called.
        Console::WriteLine("Unable to call the DoSomething method: {0}",
            ex->Message);
    }

    try
    {
        // Attempt to access a static AField field defined in the App class.
        // However, because the App class does not define this field,
        // a MissingFieldException is thrown.
        App::typeid->InvokeMember("AField", BindingFlags::Static |
            BindingFlags::SetField, nullptr, nullptr, gcnew array<Object^>{5});
    }
    catch (MissingFieldException^ ex)
    {
        // Show the user that the AField field cannot be accessed.
        Console::WriteLine("Unable to access the AField field: {0}",
            ex->Message);
    }

    try
    {
        // Attempt to access a static AnotherField field defined in the App class.
        // However, because the App class does not define this field,
        // a MissingFieldException is thrown.
        App::typeid->InvokeMember("AnotherField", BindingFlags::Static |
            BindingFlags::GetField, nullptr, nullptr, nullptr);
    }
    catch (MissingMemberException^ ex)
    {
        // Notice that this code is catching MissingMemberException which is the
        // base class of MissingMethodException and MissingFieldException.
        // Show the user that the AnotherField field cannot be accessed.
        Console::WriteLine("Unable to access the AnotherField field: {0}",
            ex->Message);
    }
}
// This code produces the following output.
//
// Unable to call the DoSomething method: Method 'App.DoSomething' not found.
// Unable to access the AField field: Field 'App.AField' not found.
// Unable to access the AnotherField field: Field 'App.AnotherField' not found.

using System;
using System.Reflection;

public class App
{
    public static void Main()
    {

        try
        {
            // Attempt to call a static DoSomething method defined in the App class.
            // However, because the App class does not define this method,
            // a MissingMethodException is thrown.
            typeof(App).InvokeMember("DoSomething", BindingFlags.Static |
                BindingFlags.InvokeMethod, null, null, null);
        }
        catch (MissingMethodException e)
        {
            // Show the user that the DoSomething method cannot be called.
            Console.WriteLine("Unable to call the DoSomething method: {0}", e.Message);
        }

        try
        {
            // Attempt to access a static AField field defined in the App class.
            // However, because the App class does not define this field,
            // a MissingFieldException is thrown.
            typeof(App).InvokeMember("AField", BindingFlags.Static | BindingFlags.SetField,
                null, null, new Object[] { 5 });
        }
        catch (MissingFieldException e)
        {
         // Show the user that the AField field cannot be accessed.
         Console.WriteLine("Unable to access the AField field: {0}", e.Message);
        }

        try
        {
            // Attempt to access a static AnotherField field defined in the App class.
            // However, because the App class does not define this field,
            // a MissingFieldException is thrown.
            typeof(App).InvokeMember("AnotherField", BindingFlags.Static |
                BindingFlags.GetField, null, null, null);
        }
        catch (MissingMemberException e)
        {
         // Notice that this code is catching MissingMemberException which is the
         // base class of MissingMethodException and MissingFieldException.
         // Show the user that the AnotherField field cannot be accessed.
         Console.WriteLine("Unable to access the AnotherField field: {0}", e.Message);
        }
    }
}
// This code example produces the following output:
//
// Unable to call the DoSomething method: Method 'App.DoSomething' not found.
// Unable to access the AField field: Field 'App.AField' not found.
// Unable to access the AnotherField field: Field 'App.AnotherField' not found.

open System
open System.Reflection

type App = class end

try
    // Attempt to call a static DoSomething method defined in the App class.
    // However, because the App class does not define this method,
    // a MissingMethodException is thrown.
    typeof<App>.InvokeMember("DoSomething", BindingFlags.Static ||| BindingFlags.InvokeMethod, null, null, null)
    |> ignore
with :? MissingMethodException as e ->
    // Show the user that the DoSomething method cannot be called.
    printfn $"Unable to call the DoSomething method: {e.Message}"

try
    // Attempt to access a static AField field defined in the App class.
    // However, because the App class does not define this field,
    // a MissingFieldException is thrown.
    typeof<App>.InvokeMember("AField", BindingFlags.Static ||| BindingFlags.SetField, null, null, [| box 5 |])
    |> ignore
with :? MissingFieldException as e ->
    // Show the user that the AField field cannot be accessed.
    printfn $"Unable to access the AField field: {e.Message}"

try
    // Attempt to access a static AnotherField field defined in the App class.
    // However, because the App class does not define this field,
    // a MissingFieldException is thrown.
    typeof<App>.InvokeMember("AnotherField", BindingFlags.Static ||| BindingFlags.GetField, null, null, null)
    |> ignore
with :? MissingMemberException as e ->
    // Notice that this code is catching MissingMemberException which is the
    // base class of MissingMethodException and MissingFieldException.
    // Show the user that the AnotherField field cannot be accessed.
    printfn $"Unable to access the AnotherField field: {e.Message}"
// This code example produces the following output:
//     Unable to call the DoSomething method: Method 'App.DoSomething' not found.
//     Unable to access the AField field: Field 'App.AField' not found.
//     Unable to access the AnotherField field: Field 'App.AnotherField' not found.

Imports System.Reflection

Public Class App
    Public Shared Sub Main() 
        Try
            ' Attempt to call a static DoSomething method defined in the App class.
            ' However, because the App class does not define this method, 
            ' a MissingMethodException is thrown.
            GetType(App).InvokeMember("DoSomething", BindingFlags.Static Or BindingFlags.InvokeMethod, _
                                       Nothing, Nothing, Nothing)
        Catch e As MissingMethodException
            ' Show the user that the DoSomething method cannot be called.
            Console.WriteLine("Unable to call the DoSomething method: {0}", e.Message)
        End Try
        Try
            ' Attempt to access a static AField field defined in the App class.
            ' However, because the App class does not define this field, 
            ' a MissingFieldException is thrown.
            GetType(App).InvokeMember("AField", BindingFlags.Static Or BindingFlags.SetField, _
                                       Nothing, Nothing, New [Object]() {5})
        Catch e As MissingFieldException
            ' Show the user that the AField field cannot be accessed.
            Console.WriteLine("Unable to access the AField field: {0}", e.Message)
        End Try
        Try
            ' Attempt to access a static AnotherField field defined in the App class.
            ' However, because the App class does not define this field, 
            ' a MissingFieldException is thrown.
            GetType(App).InvokeMember("AnotherField", BindingFlags.Static Or BindingFlags.GetField, _
                                       Nothing, Nothing, Nothing)
        Catch e As MissingMemberException
            ' Notice that this code is catching MissingMemberException which is the  
            ' base class of MissingMethodException and MissingFieldException.
            ' Show the user that the AnotherField field cannot be accessed.
            Console.WriteLine("Unable to access the AnotherField field: {0}", e.Message)
        End Try
    End Sub 
End Class 
' This code example produces the following output:
'
' Unable to call the DoSomething method: Method 'App.DoSomething' not found.
' Unable to access the AField field: Field 'App.AField' not found.
' Unable to access the AnotherField field: Field 'App.AnotherField' not found.

注解

如果代码尝试访问类不存在的成员，则通常会生成编译错误。 MissingMemberException 旨在处理在一个程序集中删除或重命名字段或方法的情况，并且更改不会反映在第二个程序集中。 在运行时，当第二个程序集中的代码尝试访问第一个程序集中缺少的成员时，将引发 MissingMemberException。

MissingMemberException 是 MissingFieldException 和 MissingMethodException的基类。 一般情况下，最好使用 MissingMemberException 派生类之一来更准确地指示错误的确切性质。 如果只想捕获缺少成员错误的一般情况，则引发 MissingMemberException。

MissingMemberException 使用具有值0x80131512的 HRESULT COR_E_MISSINGMEMBER。

有关 MissingMemberException实例的初始属性值列表，请参阅 MissingMemberException 构造函数。

构造函数

MissingMemberException()	初始化 MissingMemberException 类的新实例。
MissingMemberException(SerializationInfo, StreamingContext)	已过时. 使用序列化的数据初始化 MissingMemberException 类的新实例。
MissingMemberException(String, Exception)	使用指定的错误消息和对此异常的根本原因的内部异常的引用初始化 MissingMemberException 类的新实例。
MissingMemberException(String, String)	使用指定的类名和成员名称初始化 MissingMemberException 类的新实例。
MissingMemberException(String)	使用指定的错误消息初始化 MissingMemberException 类的新实例。

字段

ClassName	保留缺失成员的类名。
MemberName	保留缺失成员的名称。
Signature	保存缺失成员的签名。

属性

Data	获取键/值对的集合，这些键/值对提供有关异常的其他用户定义的信息。 (继承自 Exception)
HelpLink	获取或设置与此异常关联的帮助文件的链接。 (继承自 Exception)
HResult	获取或设置 HRESULT，它是分配给特定异常的编码数值。 (继承自 Exception)
InnerException	获取导致当前异常的 Exception 实例。 (继承自 Exception)
Message	获取显示类名、成员名称和缺失成员签名的文本字符串。
Source	获取或设置导致错误的应用程序或对象的名称。 (继承自 Exception)
StackTrace	获取调用堆栈上即时帧的字符串表示形式。 (继承自 Exception)
TargetSite	获取引发当前异常的方法。 (继承自 Exception)

方法

Equals(Object)	确定指定的对象是否等于当前对象。 (继承自 Object)
GetBaseException()	在派生类中重写时，返回一个或多个后续异常的根本原因 Exception。 (继承自 Exception)
GetHashCode()	用作默认哈希函数。 (继承自 Object)
GetObjectData(SerializationInfo, StreamingContext)	已过时. 使用类名、成员名称、缺失成员的签名和其他异常信息设置 SerializationInfo 对象。
GetType()	获取当前实例的运行时类型。 (继承自 Exception)
MemberwiseClone()	创建当前 Object的浅表副本。 (继承自 Object)
ToString()	创建并返回当前异常的字符串表示形式。 (继承自 Exception)

事件

SerializeObjectState

已过时. 序列化异常以创建包含有关异常的序列化数据的异常状态对象时发生。 (继承自 Exception)

另请参阅

• Exception
• MissingFieldException
• MissingMethodException
• 处理和引发异常