gistfile1.cs

		public static bool IsManagedAssembly (string file)
		{
			try {
				using (Stream fs = new FileStream (file, FileMode.Open, FileAccess.Read, FileShare.ReadWrite)) {
					BinaryReader reader = new BinaryReader(fs);
					
					//The 4-byte PE Header indicator is at 0x3C
					fs.Position = 0x3C;
					uint peHeader = reader.ReadUInt32();
					
					//Jump to the CLR header start location at 0xE8 past the PE header 
					fs.Position = peHeader + 0xe8;
					
					// These two bytes will be nonzero for managed assemblies, 
					// and zero for native dlls
					return (0UL != reader.ReadUInt64 ());
				}// using fs
			} catch { } // Don't care
			return false;
		}