Sample code to retrieve more than 5000 records using FetchXML in CRM

private List<Entity> GetTotalRecordsfromFetch(string fetchXML, IOrganizationService orgService)
{
List<Entity> lstEntity = new List<Entity>();

int fetchCount = 5000;
int pageNumber = 1;
string pagingCookie = null;

while (true)
{
// Build fetchXml string with the placeholders.
string xml = this.CreateXml(fetchXML, pagingCookie, pageNumber, fetchCount);
RetrieveMultipleRequest fetchRequest = new RetrieveMultipleRequest
{
Query = new FetchExpression(xml)
};

var returnCollections = ((RetrieveMultipleResponse)orgService.Execute(fetchRequest)).EntityCollection;

if (returnCollections.Entities.Count >= 1)
{
lstEntity.AddRange(returnCollections.Entities);
}

if (returnCollections.MoreRecords)
{
pageNumber++;

results.pagingCookie = returnCollections.PagingCookie;
}
else
{
// If no more records in the result nodes, exit the loop.
break;
}
}

return lstEntity;
}

public string CreateXml(string xml, string cookie, int page, int count)
{
StringReader stringReader = new StringReader(xml);
XmlTextReader reader = new XmlTextReader(stringReader);

XmlDocument doc = new XmlDocument();
doc.Load(reader);

XmlAttributeCollection attrs = doc.DocumentElement.Attributes;

if (cookie != null)
{
XmlAttribute pagingAttr = doc.CreateAttribute("paging-cookie");
pagingAttr.Value = cookie;
attrs.Append(pagingAttr);
}

XmlAttribute pageAttr = doc.CreateAttribute("page");
pageAttr.Value = System.Convert.ToString(page);
attrs.Append(pageAttr);

XmlAttribute countAttr = doc.CreateAttribute("count");
countAttr.Value = System.Convert.ToString(count);
attrs.Append(countAttr);

StringBuilder sb = new StringBuilder(1024);
StringWriter stringWriter = new StringWriter(sb);

XmlTextWriter writer = new XmlTextWriter(stringWriter);
doc.WriteTo(writer);
writer.Close();

return sb.ToString();
}

private static List<Entity> GetTotalRecordsFetchXML(OrganizationServiceProxy orgProxy, string fetchXML)
{
XDocument xDocument = XDocument.Parse(fetchXML);
var fetchXmlEntity = xDocument.Root.Element("entity").ToString();

EntityCollection entityColl = new EntityCollection();
List<Entity> lstEntity = new List<Entity>();
int page = 1;
do
{

entityColl = orgProxy.RetrieveMultiple(new FetchExpression(
string.Format("<fetch version='1.0' page='{1}' paging-cookie='{0}'>" + fetchXmlEntity + "</fetch>",
SecurityElement.Escape(entityColl.PagingCookie), page++)));

lstEntity.AddRange(entityColl.Entities);
}
while (entityColl.MoreRecords);

return lstEntity;
}