分页代码

 1 /// <summary>
 2         /// 生成页码的html
 3         /// </summary>
 4         /// <param name="urlFormat">超链接的格式。list.ashx?pagenum={pagenum}。地址中用{pagenum}做为当前页码的占位符</param>
 5         /// <param name="totalSize">总数据条数</param>
 6         /// <param name="pageSize">每页多少条数据 </param>
 7         /// <param name="currentPage">当前页的页码</param>
 8         /// <returns></returns>
 9         public static RawString Pager(string urlFormat, long totalSize,
10             long pageSize, long currentPage)
11         {
12             StringBuilder sb = new StringBuilder();
13             //currentPage当前页的页面。在当前页之前显示最多5个、之后显示最多5个。
14             // 15,16,17,18,19,(20),21,22,23,24,25
15             // 1,2,(3),4,5,6,7,8
16             //一共50页， 43,44,45,46,,47(48),49,50
17             //for(int i=)
18  
19             //总页数
20             long totalPageCount = (long)Math.Ceiling((totalSize*1.0f)/(pageSize*1.0f));
21             //58*1.0f/10*1.0f=5.8，6
22             //60*1.0f/10*.1.f=6
23             //61*1.0f/10*1.0f=6.1=7
24  
25             //在当前页面前后各最多显示5个页码
26             //计算页码条中第一条的页码
27             long firstPageNum = Math.Max(currentPage - 5, 1);
28             //计算页码条中最后一条的页码
29             long lastPageNum = Math.Min(currentPage + 5, totalPageCount);
30  
31             sb.AppendLine("<li><a href=‘" + 
32                 urlFormat.Replace("{pagenum}","1") + "‘>首页</a></li>");
33             for (long i = firstPageNum; i <= lastPageNum; i++)
34             {
35                 string url = urlFormat.Replace("{pagenum}",i.ToString());
36                 if (i == currentPage)
37                 {
38                     sb.Append("<li class=‘active‘><a>" + i + "</a></li>");
39                 }
40                 else
41                 {
42                     sb.Append("<li><a href=‘" + url + "‘>" + i + "</a></li>");
43                 }                
44             }
45             sb.AppendLine("<li><a href=‘" +
46                 urlFormat.Replace("{pagenum}", totalPageCount.ToString()) + "‘>末页</a></li>");
47             return new RawString(sb.ToString());
48         }