OpenWriteCompletedEventHandler 代理人

定義

命名空間:

System.Net

組件:

netstandard.dll, System.Net.WebClient.dll

代表將處理 OpenWriteCompleted 之 WebClient 事件的方法。

C#

public delegate void OpenWriteCompletedEventHandler(object sender, OpenWriteCompletedEventArgs e);

參數

sender

Object

事件的來源。

e

OpenWriteCompletedEventArgs

OpenWriteCompletedEventArgs，包含事件資料。

範例

下列程式代碼範例示範如何開啟數據流以寫入要上傳的數據。

C#

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

    // Specify that the OpenWriteCallback method gets called
    // when the writeable stream is available.
    client.OpenWriteCompleted += new OpenWriteCompletedEventHandler(OpenWriteCallback2);
    client.OpenWriteAsync(uri);
    // Applications can perform other tasks
    // while waiting for the upload to complete.
}

當數據流可供使用時，會呼叫下列方法。

C#

private static void OpenWriteCallback2(Object sender, OpenWriteCompletedEventArgs e)
{
    Stream body = null;
    StreamWriter s = null;

    try
    {
        body = (Stream)e.Result;
        s = new StreamWriter(body);
        s.AutoFlush = true;
        s.Write("This is content data to be sent to the server.");
    }
    finally
    {
        if (s != null)
        {
            s.Close();
        }

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

備註

建立 OpenWriteCompletedEventHandler 委派時，必須識別處理事件的方法。 若要使事件與您的事件處理常式產生關聯，請將委派的執行個體 (Instance) 加入至事件。 除非您移除委派，否則每當事件發生時就會呼叫事件處理常式。

擴充方法

GetMethodInfo(Delegate)

取得表示特定委派所代表之方法的物件。

適用於