OBReader1.cs

using System.Collections.Generic;
using System.IO;
using System.Linq;
using OpenBabel;

namespace OBDotNetExamples
{
    public static class OBReader
    {
        private static OBConversion obc;

        //store the supported file formats.
        private static HashSet<string> validExt;

        static OBReader()
        {
            obc = new OBConversion();
            validExt = new HashSet<string>();

            foreach(string s in obc.GetSupportedInputFormat())
            {
                validExt.Add(s.Remove(s.IndexOf(' ')));    
            }
        }

        public static OBMol ReadMol(string fileName)
        {
            return ReadFiles(fileName).First();
        }

        public static IEnumerable<OBMol> ReadFiles(params string[] fileNames)
        {
            OBMol obMol = new OBMol();
            
            foreach (string fileName in fileNames)
            {

                if (!File.Exists(fileName))
                    throw new FileNotFoundException("Could not find file : " + fileName);

                string ext = fileName.Substring(fileName.LastIndexOf(".") + 1);

                if (!validExt.Contains(ext))
                    throw new IOException("Unsupported file type: " + fileName);
                
                
                obc.SetInFormat(ext);

                if(obc.ReadFile(obMol,fileName))
                    yield return obMol;
               
                while(obc.Read(obMol))
                    yield return obMol;

            }
        }//end ReadFiles(params string[] files)
    
    }
}