WebClient.DownloadProgressChanged 이벤트

정의

비동기 다운로드 작업을 통해 데이터 전체 또는 일부를 성공적으로 전송하면 발생합니다.Occurs when an asynchronous download operation successfully transfers some or all of the data.

public:
 event System::Net::DownloadProgressChangedEventHandler ^ DownloadProgressChanged;
public event System.Net.DownloadProgressChangedEventHandler DownloadProgressChanged;
member this.DownloadProgressChanged : System.Net.DownloadProgressChangedEventHandler 
Public Custom Event DownloadProgressChanged As DownloadProgressChangedEventHandler 
Public Event DownloadProgressChanged As DownloadProgressChangedEventHandler 

예제

다음 코드 예제에서는이 이벤트에 대 한 이벤트 처리기를 설정 하는 방법을 보여 줍니다.The following code example demonstrates setting an event handler for this event.

// Sample call : DownLoadFileInBackground2 ("http://www.contoso.com/logs/January.txt");
void DownLoadFileInBackground2( String^ address )
{
   WebClient^ client = gcnew WebClient;
   Uri ^uri = gcnew Uri(address);
   
   // Specify that the DownloadFileCallback method gets called
   // when the download completes.
   client->DownloadFileCompleted += gcnew AsyncCompletedEventHandler( DownloadFileCallback2 );
   
   // Specify a progress notification handler.
   client->DownloadProgressChanged += gcnew DownloadProgressChangedEventHandler( DownloadProgressCallback );
   client->DownloadFileAsync( uri, "serverdata.txt" );
}


// Sample call : DownLoadFileInBackground2 ("http://www.contoso.com/logs/January.txt");
public static void DownLoadFileInBackground2 (string address)
{
    WebClient client = new WebClient ();
    Uri uri = new Uri(address);

    // Specify that the DownloadFileCallback method gets called
    // when the download completes.
    client.DownloadFileCompleted += new AsyncCompletedEventHandler (DownloadFileCallback2);
    // Specify a progress notification handler.
    client.DownloadProgressChanged += new DownloadProgressChangedEventHandler(DownloadProgressCallback);
    client.DownloadFileAsync (uri, "serverdata.txt");
}

'  Sample call : DownLoadFileInBackground2 ("http:' www.contoso.com/logs/January.txt")
Public Shared Sub DownLoadFileInBackground2(ByVal address As String)

    Dim client As WebClient = New WebClient()

    '  Specify that the DownloadFileCallback method gets called
    '  when the download completes.
    AddHandler client.DownloadFileCompleted, AddressOf DownloadFileCallback2
    '  Specify a progress notification handler.
    AddHandler client.DownloadProgressChanged, AddressOf DownloadProgressCallback
                Dim uri as Uri = New Uri(address)
    client.DownloadFileAsync(uri, "serverdata.txt")
End Sub

다음 코드 예제에는이 이벤트 처리기의 구현을 보여 줍니다.The following code example shows an implementation of a handler for this event.

static void UploadProgressCallback(Object^ sender, 
          UploadProgressChangedEventArgs^ e)
      {
          // Displays the operation identifier, and the transfer progress.
          Console::WriteLine("{0}    uploaded {1} of {2} bytes. {3} % complete...", 
              (String ^)e->UserState, 
              e->BytesSent, 
              e->TotalBytesToSend,
              e->ProgressPercentage);
      }
static void DownloadProgressCallback(Object^ sender, 
          DownloadProgressChangedEventArgs^ e)
      {
          // Displays the operation identifier, and the transfer progress.
          Console::WriteLine("{0}    downloaded {1} of {2} bytes. {3} % complete...", 
              (String ^)e->UserState, 
              e->BytesReceived, 
              e->TotalBytesToReceive,
              e->ProgressPercentage);
      }
private static void UploadProgressCallback(object sender, UploadProgressChangedEventArgs e)
{
    // Displays the operation identifier, and the transfer progress.
    Console.WriteLine("{0}    uploaded {1} of {2} bytes. {3} % complete...", 
        (string)e.UserState, 
        e.BytesSent, 
        e.TotalBytesToSend,
        e.ProgressPercentage);
}
private static void DownloadProgressCallback(object sender, DownloadProgressChangedEventArgs e)
{
    // Displays the operation identifier, and the transfer progress.
    Console.WriteLine("{0}    downloaded {1} of {2} bytes. {3} % complete...", 
        (string)e.UserState, 
        e.BytesReceived, 
        e.TotalBytesToReceive,
        e.ProgressPercentage);
}
Private Shared Sub UploadProgressCallback(ByVal sender As Object, ByVal e As UploadProgressChangedEventArgs)

    '  Displays the operation identifier, and the transfer progress.
    Console.WriteLine("{0}    uploaded {1} of {2} bytes. {3} % complete...", _
     CStr(e.UserState), e.BytesSent, e.TotalBytesToSend, e.ProgressPercentage)
End Sub
Private Shared Sub DownloadProgressCallback(ByVal sender As Object, ByVal e As DownloadProgressChangedEventArgs)

    '  Displays the operation identifier, and the transfer progress.
    Console.WriteLine("0}    downloaded 1} of 2} bytes. 3} % complete...", _
     CStr(e.UserState), e.BytesReceived, e.TotalBytesToReceive, e.ProgressPercentage)
End Sub

설명

이 이벤트는 비동기 다운로드 진행 될 때마다 발생 합니다.This event is raised each time an asynchronous download makes progress. 이 이벤트는 다음 방법 중 하나를 사용 하 여 다운로드를 시작 하면 발생 합니다.This event is raised when downloads are started using any of the following methods.

방법Method DescriptionDescription
DownloadDataAsync 호출 스레드를 차단 하지 않고 리소스에서 데이터를 다운로드 하 고 Byte 배열을 반환 합니다.Downloads data from a resource and returns a Byte array, without blocking the calling thread.
DownloadFileAsync 호출 스레드를 차단 하지 않고 리소스에서 데이터를 로컬 파일로 다운로드 합니다.Downloads data from a resource to a local file, without blocking the calling thread.
OpenReadAsync 호출 스레드를 차단 하지 않고 리소스에서 데이터를 반환 합니다.Returns the data from a resource, without blocking the calling thread.

DownloadProgressChangedEventHandler은이 이벤트에 대 한 대리자입니다.The DownloadProgressChangedEventHandler is the delegate for this event. DownloadProgressChangedEventArgs 클래스는 이벤트 데이터에 이벤트 처리기를 제공 합니다.The DownloadProgressChangedEventArgs class provides the event handler with event data.

이벤트를 처리 하는 방법에 대 한 자세한 내용은 참조 하세요. 이벤트 처리 및 발생합니다.For more information about how to handle events, see Handling and Raising Events.

참고

수동 FTP 파일 전송 서버는 파일 크기를 보내지 않은 이므로 항상 0의 진행률 백분율을 표시 됩니다.A passive FTP file transfer will always show a progress percentage of zero, since the server did not send the file size. 진행률을 표시 하려면 GetWebRequest 가상 메서드를 재정의 하 여 FTP 연결을 활성으로 변경할 수 있습니다.To show progress, you can change the FTP connection to active by overriding the GetWebRequest virtual method:

internal class MyWebClient : WebClient
{  
    protected override WebRequest GetWebRequest(Uri address)
    {  
        FtpWebRequest req = (FtpWebRequest)base.GetWebRequest(address);  
        req.UsePassive = false;  
        return req;  
    }  
}  

적용 대상