没有调用UploadProgressChanged事件 [英] UploadProgressChanged Event Not Being Called

问题描述

我正在使用下面显示的UploadFilesAsync方法上传文件.

I'm uploading files using the UploadFilesAsync method shown below.

var wc = new WebClient();
Uri myUri = new Uri(uriString);
wc.UploadFileAsync(myUri, "POST", filePath);
wc.UploadProgressChanged += new UploadProgressChangedEventHandler(wc_UploadProgressChanged);
wc.UploadFileCompleted += new UploadFileCompletedEventHandler(wc_UploadFileCompleted);

调用了我的UploadFileCompleted事件处理程序，但是由于某种原因，从不调用UploadProgressChanged事件处理程序.

My UploadFileCompleted event handler is called, but for some reason the UploadProgressChanged event handler is never called.

有什么想法吗?

推荐答案

更改:

wc.UploadFileAsync(myUri, "POST", filePath);
wc.UploadProgressChanged += new UploadProgressChangedEventHandler(wc_UploadProgressChanged);
wc.UploadFileCompleted += new UploadFileCompletedEventHandler(wc_UploadFileCompleted);

针对:

wc.UploadProgressChanged += new UploadProgressChangedEventHandler(wc_UploadProgressChanged);
wc.UploadFileCompleted += new UploadFileCompletedEventHandler(wc_UploadFileCompleted);
wc.UploadFileAsync(myUri, "POST", filePath);

您要绑定事件之后，必须绑定事件处理程序 首先.

You are binding the event AFTER the UploadFileAsync call, you must bind event handlers first.

MSDN示例:

// 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.");
}

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