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