Question

I have met an issue regarding the casting type from HttpInputStream to FileStream.

How I did ?

I have a HttpPostedFileBase object and I want to have FileStream.

I wrote:

public void Test(HttpPostedFileBase postedFile) {
  FileStream fileStream = (FileStream)(postedFile.InputStream); // throw exception

  FileStream anotherFileStream = postedFile.InputStream as FileStream; // null
}

I tried also

public void Test(HttpPostedFileBase postedFile) {
  Stream stream = postedFile.InputStream as Stream;

  FileStream myFile = (FileStream)stream;

}

But no success.

Why at postedFile.InputStream comes HttpInputStream type ?

And how could I solve this issue ?

Thanks

Answer 1

The stream that you get from your HTTP call is read-only sequential (non-seekable) and the FileStream is read/write seekable. You will need first to read the entire stream from the HTTP call into a byte array, then create the FileStream from that array.