一个分页页码函数

说明下：参数PageIndex是从0开始；参数PageCount表示需要分页的数量；
using System;
using System.Collections.Generic;

public class MyClass
{
    static int startIndex,endIndex;
    static int pageSize=4;
    static int pageCount=13;
    public static void RunSnippet()
    {
        for(int i=0;i<21;i++)
            g(i);
    }
    static void g(int pageIndex)
    {
        GetPageArea(ref startIndex,ref endIndex,pageIndex,pageSize,pageCount);
        WL("Page{2}\tArea is : \t{0} \t-- \t{1}",startIndex,endIndex,pageIndex);
    }
         static   void GetPageArea(ref int startIndex, ref int endIndex, int pageIndex, int pageSize, int pageCount)
        {
            if ( pageSize < 0 || pageCount < 0)
                throw new ArgumentException("Maybe args too big!");

            if (pageSize == 0 || pageCount == 0)
            {
                startIndex = 0;
                endIndex = 0;
                return;
            }

            if (pageIndex <= pageSize/2)
            {
                startIndex = 0;
                endIndex = pageSize - 1;
                return;
            }
            if (pageIndex > pageCount-pageSize/2-1)
            {
                startIndex = pageCount - pageSize;
                endIndex = pageCount - 1;
                return;
            }

            startIndex = pageIndex - pageSize / 2;
            endIndex = pageIndex + pageSize / 2 - (pageSize % 2 == 1 ? 0 : 1);
        }
    #region Helper methods
    
    public static void Main()
    {
        try
        {
            RunSnippet();
        }
        catch (Exception e)
        {
            string error = string.Format("---\nThe following error occurred while executing the snippet:\n{0}\n---", e.ToString());
            Console.WriteLine(error);
        }
        finally
        {
            Console.Write("Press any key to continue...");
            Console.ReadKey();
        }
    }

    private static void WL(object text, params object[] args)
    {
        Console.WriteLine(text.ToString(), args);    
    }
    
    private static void RL()
    {
        Console.ReadLine();    
    }
    
    private static void Break() 
    {
        System.Diagnostics.Debugger.Break();
    }

    #endregion
}