CopyToDataTable不会在linq中显示为方法

Question

linq的新手并尝试实现

  select * from tblCountries order by CountryName

我按照http://msdn.microsoft.com/en-us/library/bb669096%28v=vs.110%29.aspx中的程序进行操作，现在可以访问CopyToDataTable方法了。

但是现在orderby部分存在语法错误 -

cannot convert IOrderedQueryable<Context.tblCountry> to Ienumerable<system.data.datarow>

码

public DataTable GetAllRecords(bool bDeleted)
{
  IEnumerable<DataRow> query = (from p in MedianDB.tblCountries
                              select p).OrderBy(p => p.CountryName);//error here                                        

    DataTable dt = query.CopyToDataTable<DataRow>();

    if (dt != null)
        return dt;
    else
        return dt;
}