IEnumerable

using System;
using System.Collections.Generic;
using System.Linq;
 
class Program
{
 
    static void Main(string[] args)
    {
        var nums = GetAllNumber();
        //var nums = GetAllNumber().ToList();
        var t = nums.Skip(100000).Take(2000).Where(x => x % 7 == 0);
        foreach(int i in t)
        {
            Console.Write("{0}\t", i.ToString());
        }
    }
     
    static IEnumerable<int> GetAllNumber()
    {
        for (int i = 0;i<int.MaxValue;i++)
        {
            yield return i;
        }
        yield return int.MaxValue;
    }
}

扩展方法：
public static DataTable ConvertToDataTable(this IEnumerable enumerable)
 {
     var dataTable = new DataTable();
     foreach (PropertyDescriptor pd in TypeDescriptor.GetProperties(typeof(T))) {
            dataTable.Columns.Add(pd.Name, pd.PropertyType);
     }
     foreach (T item in enumerable) {
            var Row = dataTable.NewRow();
                
        foreach (PropertyDescriptor dp in TypeDescriptor.GetProperties(typeof(T)))  {
                  Row[pd.Name] = pd.GetValue(item);
        }
     dataTable.Rows.Add(Row);
    }
    return dataTable;

}

 

传统写法：
DataTable table = new DataTable();
 table.Columns.Add("UserID", typeof (long));
 table.Columns.Add("UserName", typeof (string));

IEnumerable<T> database = //获取数据源；
    foreach (T info in database) {
         DataRow row = dt.NewRow();
         row["ID"] = database.ID;
         row["Name"] = database.Name;
         table.Rows.Add(row);
      }
 }
 return table;

ObjectQuery 
ToTraceString()

DECLARE @pageSize INT ;
DECLARE @pageIndex INT ;
SET @pageSize = ５
SET @pageIndex =２ ;
 --第二页，每页显示５条数据                      
SELECT  *
FROM    ( SELECT    ROW_NUMBER() OVER ( ORDER BY CreateDate ASC ) AS 'rowNumber' ,
                    *
          FROM      dbo.Task_Info
        ) AS temp
WHERE   rowNumber BETWEEN ( ( ( @pageIndex - 1 ) * @pageSize ) + 1 )
                  AND     ( @pageIndex * @pageSize )


        public static  string ToTraceString<T>(this IQueryable<T> query)  

        {

            return ((System.Data.Objects.ObjectQuery) query).ToTraceString();

        }

 

//调用

 query.ToTraceString();