web api 2 file upload error

Question

I'm using this code to process a file upload to a web api:

[HttpPost]
public async Task<IHttpActionResult> Post(string provider)
{  
    if (!Request.Content.IsMimeMultipartContent())
        throw new Exception();

    var streamProvider = new MultipartMemoryStreamProvider();
    await Request.Content.ReadAsMultipartAsync(streamProvider); // FAILS HERE
    foreach (var file in streamProvider.Contents)
    {
        var imageFilename = file.Headers.ContentDisposition.FileName.Trim('\"');
        var imageStream = await file.ReadAsStreamAsync();

    }
}

but it throws an error here: await Request.Content.ReadAsMultipartAsync(streamProvider);

The error is: Error reading MIME multipart body part. The inner Exception is:

{"Cannot access a disposed object."}

any ideas on why this error is coming up?

@user3629247 He has the exception already why would he need a trycatch? he wouldnt be posting here if he was ignoring the problem — Tascalator, Jun 05 '14 at 18:39
@user441365 are you using the right Content-Type header value?? aka Content-Type: multipart/form-data — Tascalator, Jun 05 '14 at 18:40
if we wrap our method in try-catch block,we can gracefully handle any errors that occur as part of the method. for this scenario he already catch the exception — MustangManiac, Jun 05 '14 at 18:42
Are you using the [`enctype`](http://stackoverflow.com/questions/4526273/what-does-enctype-multipart-form-data-mean) attribute? — djikay, Jul 05 '14 at 01:54

score 8 · Answer 1 · answered Dec 28 '15 at 10:38

I had a similar problem but the provided solution did not work for me, so here is mine : the file you have uploaded did not match the security limits of IIS.

http://forums.asp.net/t/2062896.aspx?Error+reading+MIME+multipart+body+part+when+upload+image

<system.web>
    <httpRuntime maxRequestLength="30000000" /> <!-- if you forget this one it does not work -->
</system.web>

<system.webServer>
    <security>
      <requestFiltering>
        <requestLimits maxAllowedContentLength="30000000" />
      </requestFiltering>
    </security>
</system.webServer>

score 4 · Answer 2 · edited Oct 06 '15 at 15:34

4

I had the same exception, but for a different reason. My Post method had a return type of void. Once I changed the return type to Task<[T]>, type of string in my case, it started working.

edited Oct 06 '15 at 15:34

Felipe Oriani

37,948
19
131
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answered Oct 06 '15 at 15:00

kevinj

51
1

1

This is the common .NET "async void" problem (i.e you can not have an async method to return void) : https://msdn.microsoft.com/en-us/magazine/jj991977.aspx – Christophe Blin Dec 28 '15 at 10:39

score 3 · Accepted Answer · answered Jul 04 '14 at 17:52

Have you tried this?

[HttpPost]
public async Task<IHttpActionResult> Post(string provider)
{  
    if (!Request.Content.IsMimeMultipartContent())
        throw new Exception();

    var streamProvider = await Request.Content.ReadAsMultipartAsync(); // HERE
    foreach (var file in streamProvider.Contents)
    {
        var imageFilename = file.Headers.ContentDisposition.FileName.Trim('\"');
        var imageStream = await file.ReadAsStreamAsync();
    }
}

It looks as it should be called like this.

If I copy this code exactly, I get the disposed error right on the line with the `// HERE` comment :/ — Sinaesthetic, Aug 19 '15 at 21:37

score 0 · Answer 4 · answered Jul 04 '14 at 17:30

0

Shouldn't you have path to store uploaded files. Something like this:

var streamProvider = new MultipartMemoryStreamProvider(@"C:\Uploads");

answered Jul 04 '14 at 17:30

buggy08

130
2
9

web api 2 file upload error

4 Answers4