file转换字节

public ActionResult ImportAuditGroup([FromForm] int projectId, IFormCollection files)
{

var msBuffer =null;
foreach (var filesFile in files.Files)
{
var fileName = filesFile.FileName;//文件名
var fileExt = Path.GetExtension(fileName);//后缀
var ms = filesFile.OpenReadStream();
//打开文件流
msBuffer =StreamToBytes(ms);//文件转为字节数组
}
return File(msBuffer, "application/octet-stream");
}

public byte[] StreamToBytes(Stream stream)
{
byte[] bytes = new byte[stream.Length];
stream.Read(bytes, 0, bytes.Length);
// 设置当前流的位置为流的开始
stream.Seek(0, SeekOrigin.Begin);
return bytes;
}