string gdbpath = @"E:\newShapes.gdb";
            FileGeoDatabaseFeatureLayer.CreateFileGeoDatabase(gdbpath);
            Collection<FeatureSourceColumn> columnsTemp = new Collection<FeatureSourceColumn>();
            columnsTemp.Add(new FeatureSourceColumn("myblob", "blob", 1));

            FileGeoDatabaseFeatureLayer.CreateTable(gdbpath, "Table1", WellKnownType.Point, columnsTemp);

            FileStream pdffile = new FileStream(@"e:\yourfile", FileMode.Open);
            byte[] bytes = new byte[(int)pdffile.Length];
            pdffile.Read(bytes, 0, (int)pdffile.Length);
            pdffile.Close();

            FileGeoDatabaseFeatureLayer gdbLayer = new FileGeoDatabaseFeatureLayer(gdbpath, "table1");

            string newString = Convert.ToBase64String(bytes);
            gdbLayer.Open();
            gdbLayer.FeatureSource.BeginTransaction();
            for (int i = 0; i < 200; i++)
            {
                Feature feature = new Feature(0, 0);
                feature.ColumnValues["myblob"] = newString;
                gdbLayer.FeatureSource.AddFeature(feature);
            }
            gdbLayer.FeatureSource.CommitTransaction();

            var f = gdbLayer.FeatureSource.GetAllFeatures(ReturningColumnsType.AllColumns);