Upserting into SalesForce using .net and SOAP API

I’ve been experimenting with the classes created by Darren Terrell in the article “SalesForce integration with .net web services SOAP API” and found that there is a limit of 200 rows for upserts, so I’ve changed the Upsert() method as below to divide and submit the upserts in batches of 200 items at a time.

public UpsertResult[] Upsert(string externalID, sObject[] items)
{
   SetupService();
   // send in batches of 200 updates
   int iIndex = 0;
   List objResults = new List(items.Count());
   while (iIndex < items.Count())
   {
      sObject[] obj200Items = items.SubArray(iIndex, 200);
      objResults.AddRange( salesforceService.upsert(externalID, obj200Items) );
      iIndex += 200;
   }
   return objResults.ToArray();
 }

The SubArray method is defined as an extension below:

public static class ArrayExtensions
{
 /// <summary>
 /// Extracts a subarray of a given number of items (count) from an array starting from a given position (startIndex)
 /// </summary>
 /// <typeparam name="T"></typeparam>
 /// <param name="arr">Array from which to extract a subarray</param>
 /// <param name="startIndex">Position from where to obtain the array items</param>
 /// <param name="count">Number of items</param>
 /// <returns></returns>
 public static T[] SubArray(this T[] arr, int startIndex, int count)
 {
    var sub = new T[count];
    int iActualCount = count;
    if( arr.Count() - startIndex < count )
       iActualCount = arr.Count() - startIndex;
    Array.Copy(arr, startIndex, sub, 0, iActualCount);
    return sub;
 }
}