UploadDataCompletedEventHandler 委托

定义

public delegate void UploadDataCompletedEventHandler(System::Object ^ sender, UploadDataCompletedEventArgs ^ e);

public delegate void UploadDataCompletedEventHandler(object sender, UploadDataCompletedEventArgs e);

type UploadDataCompletedEventHandler = delegate of obj * UploadDataCompletedEventArgs -> unit

Public Delegate Sub UploadDataCompletedEventHandler(sender As Object, e As UploadDataCompletedEventArgs)

参数

示例

下面的代码示例演示如何异步上传数据。

public static void UploadDataInBackground2(string address)
{
    WebClient client = new WebClient();
    Uri uri = new Uri(address);
    string text = "Time = 12:00am temperature = 50";
    byte[] data = System.Text.Encoding.UTF8.GetBytes(text);
    string method = "POST";

    client.UploadDataCompleted += new UploadDataCompletedEventHandler(UploadDataCallback2);
    client.UploadDataAsync(uri, method, data);
}

Public Shared Sub UploadDataInBackground2(ByVal address As String)

    Dim client As WebClient = New WebClient()
    Dim text As String = "Time = 12:00am temperature = 50"
    Dim data() As Byte = System.Text.Encoding.UTF8.GetBytes(text)
    Dim method As String = "POST"

    AddHandler client.UploadDataCompleted, AddressOf UploadDataCallback2
    Dim uri as Uri = New Uri(address)
                client.UploadDataAsync(uri, method, data)
End Sub

上传完成后，将调用以下方法。

private static void UploadDataCallback2(Object sender, UploadDataCompletedEventArgs e)
{
    byte[] data = (byte[])e.Result;
    string reply = System.Text.Encoding.UTF8.GetString(data);

    Console.WriteLine(reply);
}

Private Shared Sub UploadDataCallback2(ByVal sender As Object, ByVal e As UploadDataCompletedEventArgs)

    Dim data() As Byte = CType(e.Result, Byte())
    Dim reply As String = System.Text.Encoding.UTF8.GetString(data)

    Console.WriteLine(reply)
End Sub

注解

创建 UploadDataCompletedEventHandler 委托时，需要标识将处理该事件的方法。 若要将事件与事件处理程序关联，请将该委托的一个实例添加到事件中。 除非移除了该委托，否则每当发生该事件时就会调用事件处理程序。 有关事件处理程序委托的详细信息，请参阅 处理和引发事件。