Get Response Headers From WebClient

Question

I'm trying to upload a file using WebClient, but I can't seem to find a way to get the response headers once the file is uploaded I'm using this Microsoft example to get the headers, but it just returns null. My code looks like this:

public void UploadPart(string filePath, string preSignedUrl)
{
   WebClient wc = new();
   wc.UploadProgressChanged += WebClientUploadProgressChanged;
   wc.UploadFileCompleted += WebClientUploadCompleted;
   wc.UploadFileAsync(new Uri(preSignedUrl), "PUT", filePath);

   // Obtain the WebHeaderCollection instance containing the header name/value pair from the response.
   WebHeaderCollection myWebHeaderCollection = wc.ResponseHeaders;

   System.Diagnostics.Debug.WriteLine(myWebHeaderCollection);
}

I can confirm that the headers exist because I'm able to get them using an HttpWebResponse upload implementation in another method.

dotnetstep · Accepted Answer · 2021-06-24 15:30:18Z

1

Method should be written like this.

public Task UploadPart(string filePath, string preSignedUrl)
{
   WebClient wc = new();
   wc.UploadProgressChanged += WebClientUploadProgressChanged;
   wc.UploadFileCompleted += WebClientUploadCompleted;
   await wc.UploadFileAsync(new Uri(preSignedUrl), "PUT", filePath);

   // Obtain the WebHeaderCollection instance containing the header name/value pair from the response.
   WebHeaderCollection myWebHeaderCollection = wc.ResponseHeaders;

   System.Diagnostics.Debug.WriteLine(myWebHeaderCollection);
}

Replace void with Task. Use await in UploadFileAsyn because it may possible without request complete code jump to next line.

answered Jun 24, 2021 at 15:30

dotnetstep

17.5k6 gold badges62 silver badges80 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

JMR Over a year ago

I just tried this, and it seems I need to add the async keyword to UploadPart or the method shows an error that await can only be used in an async member. When I do however, await wc.UploadFileAsync(new Uri(preSignedUrl), "PUT", filePath); displays the error: "Cannot await void"

JMR Over a year ago

Looks like I needed to use UploadFileTaskAsync in place of UploadFileAsync. In doing so, your code above works great. Could you edit your answer to use UploadFileTaskAsync and I'll mark it as correct?

Collectives™ on Stack Overflow

Get Response Headers From WebClient

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related