Detect file format, by content, not extension

Question

Hello expert devs

I need to detect the file format of JUST one file type:

oleData.mso

https://en.wikipedia.org/wiki/Compound_File_Binary_Format

Using FindMimeFromData will return Octet-Stream, no help

How to detect it?

There's OpenMcdf which I use to load the oleData.mso to it, if loaded with no exception, I consider the file to be in CFBF/ Mso format.

But this will need the whole dll to import to my VB project, any VB.net way to detect this special file type?

Please help if you can, appreciated :)

Answer 1

Try something like this:

Dim file_is_CFBF As Boolean

Using fs = File.OpenRead("path to my file...")
    Dim bytes(8 - 1) As Byte
    Dim expected_bytes As Byte() = {&HD0, &HCF, &H11, &HE0, &HA1, &HB1, &H1A, &HE1}
    fs.Read(bytes, 0, 8)
    file_is_CFBF = bytes.SequenceEqual(expected_bytes)
End Using

MsgBox(file_is_CFBF)