WebClient.UploadProgressChanged 事件

定义

命名空间:

System.Net

程序集:

System.Net.WebClient.dll

Source:

WebClient.cs

异步上传操作成功传输部分或所有数据时发生。

public:
 event System::Net::UploadProgressChangedEventHandler ^ UploadProgressChanged;

public event System.Net.UploadProgressChangedEventHandler? UploadProgressChanged;

member this.UploadProgressChanged : System.Net.UploadProgressChangedEventHandler 

Public Custom Event UploadProgressChanged As UploadProgressChangedEventHandler 

事件类型

UploadProgressChangedEventHandler

示例

下面的代码示例演示如何为此事件设置事件处理程序。

// Sample call: UploadFileInBackground2("http://www.contoso.com/fileUpload.aspx", "data.txt")
void UploadFileInBackground2( String^ address, String^ fileName )
{
   WebClient^ client = gcnew WebClient;
   Uri ^uri = gcnew Uri(address);

   client->UploadFileCompleted +=
     gcnew UploadFileCompletedEventHandler (UploadFileCallback2);

   // Specify a progress notification handler.
   client->UploadProgressChanged +=
       gcnew UploadProgressChangedEventHandler( UploadProgressCallback );
   client->UploadFileAsync( uri, "POST", fileName );
   Console::WriteLine( "File upload started." );
}

// Sample call: UploadFileInBackground2("http://www.contoso.com/fileUpload.aspx", "data.txt")
public static void UploadFileInBackground2(string address, string fileName)
{
    WebClient client = new WebClient();
    Uri uri = new Uri(address);

    client.UploadFileCompleted += new UploadFileCompletedEventHandler(UploadFileCallback2);

    // Specify a progress notification handler.
    client.UploadProgressChanged += new UploadProgressChangedEventHandler(UploadProgressCallback);
    client.UploadFileAsync(uri, "POST", fileName);
    Console.WriteLine("File upload started.");
}

'  Sample call: UploadFileInBackground2("http:' www.contoso.com/fileUpload.aspx", "data.txt")
Public Shared Sub UploadFileInBackground2(ByVal address As String, ByVal fileName As String)

    Dim client As WebClient = New WebClient()
                Dim uri as Uri =  New Uri(address)
    AddHandler client.UploadFileCompleted, AddressOf UploadFileCallback2

    '  Specify a progress notification handler.
    AddHandler client.UploadProgressChanged, AddressOf UploadProgressCallback
    client.UploadFileAsync(uri, "POST", fileName)
    Console.WriteLine("File upload started.")
End Sub

下面的代码示例演示此事件的处理程序的实现。

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

注解

谨慎

WebRequest、HttpWebRequest、ServicePoint和 WebClient 已过时，不应将其用于新开发。 请改用 HttpClient。

每次异步上传进行时都会引发此事件。 当使用以下任一方法开始上传时，将引发此事件。

方法	描述
UploadDataAsync	将 Byte 数组发送到资源，而不会阻止调用线程。
UploadFileAsync	将本地文件发送到资源，而不会阻止调用线程。
UploadValuesAsync	将 NameValueCollection 发送到资源，并返回包含任何响应的 Byte 数组，而不会阻止调用线程。

UploadProgressChangedEventHandler 是此事件的委托。 UploadProgressChangedEventArgs 类为事件处理程序提供事件数据。

有关如何处理事件的详细信息，请参阅 处理和引发事件。