c# - Cannot access a closed file when uploading to memory stream -

i trying create controller allow me save images database. far have bit of code:

/// <summary> /// handles upload /// </summary> /// <returns></returns> [httppost] [route("")] public async task<ihttpactionresult> upload() {      // if request not of multipart content, return bad request     if (!request.content.ismimemultipartcontent())         return badrequest("your form must of type multipartcontent.");      // our provider     var provider = new multipartformdatastreamprovider(configurationmanager.appsettings["uploadfolder"]);      // upload our file     await request.content.readasmultipartasync(provider);      // our file     var file = provider.contents.first();     var bytes = await file.readasbytearrayasync();      // using memorystream     using (var stream = new memorystream(bytes))     {          stream.seek(0, seekorigin.begin);          // create data         var data = "data:image/gif;base64," + convert.tobase64string(stream.toarray());          // return data         return ok(data);     } } 

but isn't working. when using block error message:

"error while copying content stream."
"cannot access closed file."

does know why?

the reason happening multipartformdatastreamprovider closes , disposes uploaded files streams after has written uploaded data file location provided when passed constructor: configurationmanager.appsettings["uploadfolder"]

to access files have been uploaded need consult file data on disk uploaded file location:

so in example code needs use this:

// read first file file data collection: var fileupload = provider.filedata.first;  // temp name , path multipartformdatastreamprovider used save file as: var temppath = fileupload.localfilename;  // read file's data temp location. var bytes = file.readallbytes(temppath); 

additionally if using small files can instead use:

multipartmemorystreamprovider

this stores file data in memory , should work expected. warned though if using large files (25mb+) wise stream disk first otherwise might out of memory exceptions .net tries hold whole file in memory.