Fix System.ArgumentOutOfRangeException: Length cannot be less than zero. (#199)

* Fix System.ArgumentOutOfRangeException: Length cannot be less than zero.

* Remove unnecessary using.

Co-authored-by: claudia <cmurialdo@gmail.com>

Author: claudiamurialdo

dotnet/src/dotnetframework/GxClasses/Storage/StorageFactory.cs

@@ -1,14 +1,10 @@
-using GeneXus.Services;
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
+using GeneXus.Services;
 
 namespace GeneXus.Storage
 {
 	public class StorageFactory
 	{
-
+		const char QUESTION_MARK = '?';
 		public static ExternalProvider GetExternalProviderFromUrl(string url, out string objectName)
 		{
 			objectName = null;
@@ -17,7 +13,8 @@ public static ExternalProvider GetExternalProviderFromUrl(string url, out string
 			{
 				if (provider.GetObjectNameFromURL(url, out objectName))
 				{
-					objectName = objectName.Substring(0, objectName.IndexOf("?"));
+					var questionMarkIndex = objectName.IndexOf(QUESTION_MARK);
+					objectName = questionMarkIndex >= 0 ? objectName.Substring(0, questionMarkIndex): objectName.Substring(0);
 					return provider;
 				}
 			}