Read a non .NET DLL version from C#?

Use the FileVersionInfo object. Here’s an example from the Microsoft website that gets the version info from notepad.exe

public void GetFileVersion() {
    // Get the file version for the notepad.
    FileVersionInfo myFileVersionInfo = FileVersionInfo.GetVersionInfo("%systemroot%\\Notepad.exe");

    // Print the file name and version number.
    textBox1.Text = "File: " + myFileVersionInfo.FileDescription + '\n' +
       "Version number: " + myFileVersionInfo.FileVersion;
 }

Stolen from here.