C# HttpClient 4.5 multipart/form-data upload

Question

Does anyone know how to use the HttpClient in .Net 4.5 with multipart/form-data upload?

I couldn\'t find any examples on the internet.

Answer 1

It works more or less like this (example using an image/jpg file):

async public Task UploadImage(string url, byte[] ImageData)
{
    var requestContent = new MultipartFormDataContent(); 
    //    here you can specify boundary if you need---^
    var imageContent = new ByteArrayContent(ImageData);
    imageContent.Headers.ContentType = 
        MediaTypeHeaderValue.Parse("image/jpeg");

    requestContent.Add(imageContent, "image", "image.jpg");

    return await client.PostAsync(url, requestContent);
}

(You can requestContent.Add() whatever you want, take a look at the HttpContent descendant to see available types to pass in)

When completed, you'll find the response content inside HttpResponseMessage.Content that you can consume with HttpContent.ReadAs*Async.