MissingFieldException Classe

Definição

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

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

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

type MissingFieldException = class
    inherit MissingMemberException
    interface ISerializable

Public Class MissingFieldException
Inherits MissingMemberException

Herança

Object

Exception

MemberAccessException

MissingMemberException

MissingFieldException

Herança

Object

Exception

SystemException

MemberAccessException

MissingMemberException

MissingFieldException

Atributos

SerializableAttribute ComVisibleAttribute

Implementações

ISerializable

Exemplos

Este exemplo mostra o que acontece se você tentar usar a reflexão para chamar um método que não existe e acessar um campo que não existe. O aplicativo se recupera capturando o MissingMethodException, MissingFieldExceptione 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.

Comentários

Normalmente, um erro de compilação é gerado se o código tenta acessar um membro inexistente de uma classe. MissingFieldException é projetado para lidar com casos em que é feita uma tentativa de acessar dinamicamente um campo renomeado ou excluído de um assembly que não é referenciado por seu nome forte. O MissingFieldException é gerado quando o código em um assembly dependente tenta acessar um campo ausente em um assembly que foi modificado.

MissingFieldException usa o COR_E_MISSINGFIELD HRESULT, que tem o valor 0x80131511.

Para obter uma lista de valores de propriedade iniciais de uma instância de MissingFieldException, consulte os construtores de MissingFieldException.

Confira também

• Exception
• Manipulando e lançando exceções