MissingFieldException Clase

Definición

public ref class MissingFieldException : MissingMemberException

public class MissingFieldException : MissingMemberException

[System.Serializable]
public class MissingFieldException : MissingMemberException

[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public class MissingFieldException : MissingMemberException

type MissingFieldException = class
    inherit MissingMemberException

type MissingFieldException = class
    inherit MissingMemberException
    interface ISerializable

[<System.Serializable>]
type MissingFieldException = class
    inherit MissingMemberException
    interface ISerializable

[<System.Serializable>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type MissingFieldException = class
    inherit MissingMemberException
    interface ISerializable

Public Class MissingFieldException
Inherits MissingMemberException

Herencia

Object

Exception

MemberAccessException

MissingMemberException

MissingFieldException

Herencia

Object

Exception

SystemException

MemberAccessException

MissingMemberException

MissingFieldException

Atributos

SerializableAttribute ComVisibleAttribute

Implementaciones

ISerializable

Ejemplos

En este ejemplo se muestra lo que sucede si intenta usar la reflexión para llamar a un método que no existe y acceder a un campo que no existe. La aplicación se recupera detectando el MissingMethodException, MissingFieldExceptiony MissingMemberException.

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.

Comentarios

Normalmente, se genera un error de compilación si el código intenta acceder a un miembro inexistente de una clase. MissingFieldException está diseñado para controlar los casos en los que se intenta acceder dinámicamente a un campo cambiado o eliminado de un ensamblado al que no hace referencia su nombre seguro. MissingFieldException se produce cuando el código de un ensamblado dependiente intenta tener acceso a un campo que falta en un ensamblado que se modificó.

MissingFieldException usa el COR_E_MISSINGFIELD HRESULT, que tiene el valor 0x80131511.

Para obtener una lista de valores de propiedad iniciales para una instancia de MissingFieldException, vea los MissingFieldException constructores.

Consulte también

• Exception
• Manejo y lanzamiento de excepciones