Question

How to get data (read file) chosen in FileUpload control without FileUpload.SaveAs Method on the server? Is it possible write it at once to some object?

Answer 1

Using FileUpload.FileContent gives you a Stream to work with.

See MSDN.

For example:

void WriteFileLength()
{
    if (fileUpload.HasFile)
    {
        var fileStream = fileUpload.FileContent;
        var messageFormat = "The file is {0} bytes in length"
        Response.Write(string.Format(messageFormat, fileStream.Length));
    }
}