The data source does not support server-side data paging

A simple ToList() on your result var should work.

Edit: As explained in comments below my answer, the reason for the error is that the data source should implement ICollection. IEnumerable does not, when you do ToList() it converts it into a list which implements ICollection.

You can use generic List<T> also. See the sample code snippet:

public List<Company> GetContactList(int startindex){    string path = Server.MapPath("~/contacts.xml");    XDocument xd = XDocument.Load(path);    IEnumerable<Company> results = (from items in xd.Elements("Company").Elements("Contact")                   select new Company                   {                       Id = items.Element("ID").Value,                       Photo = (string)items.Element("photo").Value,                       Name = (string)items.Element("Name").Value,                       BloodGroup = (string)items.Element("Bg").Value,                       Dob = (string)items.Element("dob").Value,                       Anniversery = (string)items.Element("avd").Value,                       Mobile = (string)items.Element("cnum").Value,                       designation = (string)items.Element("desig").Value,                       Team = (string)items.Element("team").Value                   }).Skip(startindex*10).Take(10);    return (List<Company>) results;}

You can also use DataSet/DataTable instead of DataReader.

.ToList() at the end of the DataSource, I am assigning worked for me like below:

gvCaseLabelsLeft.DataSource = caseLabelsList.OrderBy(c=>c.caseLabelNumber).ToList();