In C#, how can i the file extension from a byte[] audio files

Question

i got one byte data from webservice in this byte data how to get file extension in C#

Anupam Maiti · Answer

You get mime type of a file using byte data. Could you please try on below , see if it works for you - [DllImport(@ "urlmon.dll" , CharSet = CharSet.Auto)] private extern static System.UInt32 FindMimeFromData(System.UInt32 pBC, [MarshalAs(UnmanagedType.LPStr)] System.String pwzUrl, [MarshalAs(UnmanagedType.LPArray)] byte [] pBuffer, System.UInt32 cbSize, [MarshalAs(UnmanagedType.LPStr)] System.String pwzMimeProposed, System.UInt32 dwMimeFlags, out System.UInt32 ppwzMimeOut, System.UInt32 dwReserverd); byte [] document = > ; file.InputStream.Read(document, 0, file.ContentLength); System.UInt32 mimetype; FindMimeFromData(0, null , document, 256, null , 0, out mimetype, 0); System.IntPtr mimeTypePtr = new IntPtr(mimetype); string mime = Marshal.PtrToStringUni(mimeTypePtr); Marshal.FreeCoTaskMem(mimeTypePtr); if (mime == "application/pdf" ) { Response.Write( "This is Valid File" ); }

Sachin Singh · Answer

Byte[] only contains the file content and not the file type, if your web service doesn't expose Mime type (metadata) then you can't get it. Better is to directly consult the author of the Webservice.