added ToDouble as Extension Method for Strings

VectoCore/Utils/DataRowExtensionMethods.cs

 using System;
+using System.Collections;
+using System.Collections.Generic;
 using System.Data;
 using System.Globalization;
+using System.Linq;
 using TUGraz.VectoCore.Exceptions;
 
 namespace TUGraz.VectoCore.Utils
@@ -32,7 +35,7 @@ namespace TUGraz.VectoCore.Utils
 		public static double ParseDouble(this DataRow row, DataColumn column)
 		{
 			try {
-				return double.Parse(row.Field<string>(column), CultureInfo.InvariantCulture);
+				return row.Field<string>(column).ToDouble();
 			} catch (IndexOutOfRangeException e) {
 				throw new VectoException(string.Format("Field {0} was not found in DataRow.", column), e);
 			} catch (NullReferenceException e) {
@@ -49,5 +52,15 @@ namespace TUGraz.VectoCore.Utils
 				throw new VectoException(string.Format("Field {0}: {1}", column, e.Message), e);
 			}
 		}
+
+		public static double ToDouble(this string self)
+		{
+			return double.Parse(self, CultureInfo.InvariantCulture);
+		}
+
+		public static IEnumerable<double> ToDouble(this IEnumerable<string> self)
+		{
+			return self.Select(ToDouble);
+		}
 	}
 }
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