DefaultHttpHandler Clase

Definición

public ref class DefaultHttpHandler : System::Web::IHttpAsyncHandler

public class DefaultHttpHandler : System.Web.IHttpAsyncHandler

type DefaultHttpHandler = class
    interface IHttpAsyncHandler
    interface IHttpHandler

Public Class DefaultHttpHandler
Implements IHttpAsyncHandler

Herencia

Object

DefaultHttpHandler

Implementaciones

IHttpAsyncHandler IHttpHandler

Ejemplos

En el ejemplo de código siguiente se muestra cómo implementar un controlador HTTP personalizado derivando de la DefaultHttpHandler clase .

public class AsyncDefaultHttpHandler : DefaultHttpHandler
{
    private HttpContext _context;

    public override IAsyncResult BeginProcessRequest(
      HttpContext context, AsyncCallback callback, object state)
    {
        AsyncResultSample ar = new AsyncResultSample(callback, state);
        _context = context;

        return ar;
    }

    public override void EndProcessRequest(IAsyncResult result)
    {
        _context.Response.Write("EndProcessRequest called.");
    }

    // This method should not be called asynchronously.
    public override void ProcessRequest(HttpContext context)
    {
        throw new InvalidOperationException(
                  "Asynchronous processing failed.");
    }

    // Enables pooling when set to true
    public override bool IsReusable
    {
        get { return true; }
    }
}

// Tracks state between the begin and end calls.
class AsyncResultSample : IAsyncResult
{
    private AsyncCallback callback = null;
    private Object asyncState;
    private Boolean isCompleted;

    internal AsyncResultSample(AsyncCallback cb, Object state)
    {
        this.callback = cb;
        asyncState = state;
        isCompleted = false;
    }

    public object AsyncState
    {
        get
        {
            return asyncState;
        }
    }

    public bool CompletedSynchronously
    {
        get
        {
            return false;
        }
    }

    public WaitHandle AsyncWaitHandle
    {
        get
        {
            throw new InvalidOperationException(
                      "ASP.NET should not use this property .");
        }
    }

    public bool IsCompleted
    {
        get
        {
            return isCompleted;
        }
    }

    internal void SetCompleted()
    {
        isCompleted = true;
        if (callback != null)
        {
            callback(this);
        }
    }
}

Public Class defaulthttpexampleVB
    Inherits DefaultHttpHandler

    Private _context As HttpContext

    Public Overrides Function BeginProcessRequest _
        (ByVal context As HttpContext, _
         ByVal callback As AsyncCallback, _
         ByVal state As Object) As IAsyncResult

        Dim ar As New AsyncResultSample(callback, state)
        _context = context

        Return (ar)
    End Function

    Public Overrides Sub EndProcessRequest(ByVal result As IAsyncResult)
        _context.Response.Write("EndProcessRequest called.")
    End Sub

    ' This method should not be called asynchronously.
    Public Overrides Sub ProcessRequest(ByVal context As HttpContext)
        Throw New InvalidOperationException _
          ("Asynchronous processing failed.")
    End Sub

    ' Enables pooling when set to true
    Public Overrides ReadOnly Property IsReusable() As Boolean
        Get
            Return True
        End Get
    End Property
End Class

' Tracks state between the begin and end calls.
Class AsyncResultSample
    Implements IAsyncResult
    Private callback As AsyncCallback = Nothing
    Private _asyncState As Object
    Private _isCompleted As Boolean

    Friend Sub New(ByVal cb As AsyncCallback, ByVal state As Object)
        Me.callback = cb
        _asyncState = state
        _isCompleted = False
    End Sub

    Public ReadOnly Property AsyncState() As Object _
      Implements IAsyncResult.AsyncState
        Get
            Return _asyncState
        End Get
    End Property

    Public ReadOnly Property CompletedSynchronously() _
      As Boolean Implements IAsyncResult.CompletedSynchronously
        Get
            Return False
        End Get
    End Property

    Public ReadOnly Property AsyncWaitHandle() _
      As WaitHandle Implements IAsyncResult.AsyncWaitHandle
        Get
            Throw New InvalidOperationException _
              ("ASP.NET should not use this property .")
        End Get
    End Property

    Public ReadOnly Property IsCompleted() _
      As Boolean Implements IAsyncResult.IsCompleted
        Get
            Return IsCompleted
        End Get
    End Property

    Friend Sub SetCompleted()
        _isCompleted = True
        If (callback <> Nothing) Then
            callback(Me)
        End If
    End Sub
End Class

Comentarios

Un objeto DefaultHttpHandler intercepta las solicitudes entrantes en la canalización HTTP cuando se ha configurado la interceptación de solicitudes a través de Internet Information Services (IIS) 6.0 y no se aplican enlaces explícitos a la extensión solicitada.

La interceptación de solicitudes se puede configurar mediante la característica de asignación de aplicaciones comodín introducida en IIS 6.0.

La DefaultHttpHandler clase implementa la IHttpAsyncHandler interfaz para proporcionar procesamiento asincrónico de solicitudes. Para obtener información general sobre los controladores HTTP, consulte Información general sobre los controladores HTTP y los módulos HTTP. Además, para obtener más información, vea lo siguiente:

• Acerca de la creación de controladores HTTP asincrónicos, consulte Tutorial: Creación de un controlador HTTP asincrónico.

• Acerca del registro de controladores HTTP, consulte Cómo: Registrar controladores HTTP.

Las clases pueden derivar de la DefaultHttpHandler clase para proporcionar un control personalizado de las solicitudes. Un controlador HTTP asincrónico derivado de DefaultHttpHandler podría invalidar el BeginProcessRequest método para cambiar cómo se procesan las solicitudes.

Un DefaultHttpHandler no usa errores ASP.NET. El contenido existente que usa errores de IIS o un mecanismo de error personalizado de ISAPI de propriety funcionaría sin cambios.

Consulte también

• Cómo: Registrar controladores HTTP
• Cómo: Crear un controlador HTTP asincrónico