OpenReadCompletedEventArgs 類別

定義

命名空間:

System.Net

組件:

System.Net.WebClient.dll

來源:

WebClient.cs

提供 OpenReadCompleted 事件的資料。

public ref class OpenReadCompletedEventArgs : System::ComponentModel::AsyncCompletedEventArgs

public class OpenReadCompletedEventArgs : System.ComponentModel.AsyncCompletedEventArgs

type OpenReadCompletedEventArgs = class
    inherit AsyncCompletedEventArgs

Public Class OpenReadCompletedEventArgs
Inherits AsyncCompletedEventArgs

繼承

Object

EventArgs

AsyncCompletedEventArgs

OpenReadCompletedEventArgs

範例

下列程式代碼範例示範下載要讀取的資源。

void OpenResourceForReading2( String^ address )
{
   WebClient^ client = gcnew WebClient;
   Uri ^uri = gcnew Uri(address);

   client->OpenReadCompleted += gcnew OpenReadCompletedEventHandler( OpenReadCallback2 );
   client->OpenReadAsync( uri );
}

public static void OpenResourceForReading2(string address)
{
    WebClient client = new WebClient();
    Uri uri = new Uri(address);

    client.OpenReadCompleted += new OpenReadCompletedEventHandler(OpenReadCallback2);
    client.OpenReadAsync(uri);
}

Public Shared Sub OpenResourceForReading2(ByVal address As String)

    Dim client As WebClient = New WebClient()
    AddHandler client.OpenReadCompleted, AddressOf OpenReadCallback2
                Dim uri as Uri = New Uri(address)
    client.OpenReadAsync(uri)
End Sub

下載完成時會呼叫下列方法。

void OpenReadCallback2( Object^ /*sender*/, OpenReadCompletedEventArgs^ e )
{
   Stream^ reply = nullptr;
   StreamReader^ s = nullptr;
   try
   {
      reply = dynamic_cast<Stream^>(e->Result);
      s = gcnew StreamReader( reply );
      Console::WriteLine( s->ReadToEnd() );
   }
   finally
   {
      if ( s != nullptr )
      {
         s->Close();
      }
      if ( reply != nullptr )
      {
         reply->Close();
      }
   }

}

private static void OpenReadCallback2(Object sender, OpenReadCompletedEventArgs e)
{
    Stream reply = null;
    StreamReader s = null;

    try
    {
        reply = (Stream)e.Result;
        s = new StreamReader(reply);
        Console.WriteLine(s.ReadToEnd());
    }
    finally
    {
        if (s != null)
        {
            s.Close();
        }

        if (reply != null)
        {
            reply.Close();
        }
    }
}

Private Shared Sub OpenReadCallback2(ByVal sender As Object, ByVal e As OpenReadCompletedEventArgs)

    Dim reply As Stream = Nothing
    Dim s As StreamReader = Nothing

    Try

        reply = CType(e.Result, Stream)
        s = New StreamReader(reply)
        Console.WriteLine(s.ReadToEnd())
    Finally

        If Not s Is Nothing Then

            s.Close()
        End If

        If Not reply Is Nothing Then

            reply.Close()
        End If
    End Try
End Sub

備註

這個類別的實例會傳遞至 OpenReadCompletedEventHandler 方法。

屬性

Cancelled	取得值，指出非同步作業是否已取消。 (繼承來源 AsyncCompletedEventArgs)
Error	取得值，指出非同步作業期間是否發生錯誤。 (繼承來源 AsyncCompletedEventArgs)
Result	取得包含由 DownloadDataAsync 方法下載之資料的可讀取資料流。
UserState	取得非同步工作的唯一識別項。 (繼承來源 AsyncCompletedEventArgs)

方法

Equals(Object)	判斷指定的物件是否等於目前的物件。 (繼承來源 Object)
GetHashCode()	做為預設雜湊函式。 (繼承來源 Object)
GetType()	取得目前執行個體的 Type。 (繼承來源 Object)
MemberwiseClone()	建立目前 Object 的淺層複製。 (繼承來源 Object)
RaiseExceptionIfNecessary()	如果非同步作業失敗，引發使用者提供的例外狀況。 (繼承來源 AsyncCompletedEventArgs)
ToString()	傳回代表目前物件的字串。 (繼承來源 Object)