我设计此控件的背景思想：
既然我想做一个无刷新分页控件，那我觉得该控件就只需要关心如下几个因素：
1）总共有多少条记录；
2）每页多少条；
3）当前第几页；
而不需要关心如点击某个页码时，该如何去获取数据。如果连如何去获取数据的逻辑都要由该控件来实现的话，那此控件的独立性就不好了。以前我见过一些页面重定向的分页控件，此类控件都需要在当前url的基础上再添加一个PageIndex的url参数。这就使得分页控件需要关心当前url的地址。而如果借助于Ajax技术，由于页面是无刷新的，所以我想是否可以设计一个控件，该控件只负责根据上面的三个信息，生成所有相关的页码，每个页码点击时执行一个由用户指定的javascript函数，并把被点击页的页码传给该函数，然后在该javascript函数中，用户可以利用ajax技术根据自己的业务逻辑获取当前页的数据。所以，这样以来，我们就可以完全做到让分页控件只负责实现如何分页的逻辑，其他的一概不用关心；这样不是很好吗？哈哈。
控件特点：
1）代码简洁清晰，轻量级，尽量不包含任何多余的东西，这也是我一贯的作风；（为了能让大家更好更快的理解，我特地耐心的加了注释）
2）需要和无刷新技术（如Ajax）结合使用，并且需要配合一个javascript客户端分页函数，（比如TurnPage）
以下是源代码：
- C# code
/// <summary>/// An simple and utility ajax pager./// </summary>public class AjaxPager : Control{ #region Private Members private string pageHref = "<a href={1}>{0}</a>"; private string turnPage = "javascript:{0}({1});"; private string seperatorSpace = " "; #endregion #region Public Properties /// <summary> /// The min value is 1. /// </summary> public int PageIndex { get { int pageIndex = 1; int? nullableIntegerValue = GetNullableIntegerValue("PageIndex"); if (nullableIntegerValue.HasValue) { pageIndex = nullableIntegerValue.Value; } if (pageIndex < 1) { pageIndex = 1; } return pageIndex; } set { ViewState["PageIndex"] = value; } } /// <summary> /// The min value is 1. /// </summary> public int PageSize { get { int pageSize = 20; //Set the default value. int? nullableIntegerValue = GetNullableIntegerValue("PageSize"); if (nullableIntegerValue.HasValue) { pageSize = nullableIntegerValue.Value; } if (pageSize < 1) { pageSize = 1; } return pageSize; } set { ViewState["PageSize"] = value; } } /// <summary> /// This property indicates the length of the pager. That means how many page numbers the pager should display. /// E.g. PageLength = 7 means the pager can most display 7 page numbers. 1,2,3,4,5,6,7 or 30,31,32,33,34,45,36 /// Notes: The PageLength should be an Odd number, like 1,3,5,7,9,11,etc. /// The default value is 5, and the minimum value is 3. /// </summary> public int PageLength { get { int pageLength = 5; //Set the default value. int? nullableIntegerValue = GetNullableIntegerValue("PageLength"); if (nullableIntegerValue.HasValue) { pageLength = nullableIntegerValue.Value; } if (pageLength < 3) { return 3; } if (pageLength % 2 == 0) { return pageLength + 1; } return pageLength; } set { ViewState["PageLength"] = value; } } /// <summary> /// This property indicates the total page number. /// </summary> public int TotalPages { get { return CalculateTotalPages(TotalRecords); } } /// <summary> /// This property indicates the total record count. /// </summary> public int TotalRecords { get { int totalRecords = 0; int? nullableIntegerValue = GetNullableIntegerValue("TotalRecords"); if (nullableIntegerValue.HasValue) { totalRecords = nullableIntegerValue.Value; } return totalRecords; } set { ViewState["TotalRecords"] = value; } } /// <summary> /// This property represents an client javascript function name. /// This javascript function will be called when the page number is clicked. /// </summary> public string TurnPageClientFunction { get { return ViewState["TurnPageClientFunction"] as string; } set { ViewState["TurnPageClientFunction"] = value; } } #endregion #region Overrides Methods /// <summary> /// Overrides this function to render all the paging items. /// </summary> protected override void Render(HtmlTextWriter writer) { if (TotalPages <= 1) { return; } StringBuilder sb = new StringBuilder(); //append the first page. if ((PageIndex > PageLength / 2 + 1) && (TotalPages > PageLength)) { sb.Append(CreatePageHref("第一页", 1)); } sb.Append(seperatorSpace); //append the previous page. if (PageIndex > 1) { sb.Append(CreatePageHref("上一页", PageIndex - 1)); } sb.Append(seperatorSpace); //append the number pages. sb.Append(GetNumberPages()); //append the next page. if (PageIndex < TotalPages) { sb.Append(CreatePageHref("下一页", PageIndex + 1)); } sb.Append(seperatorSpace); //append the last page. if (((PageIndex + PageLength / 2) < TotalPages) && (TotalPages > PageLength)) { sb.Append(CreatePageHref("最后一页", TotalPages)); } //write the total contents. writer.Write(sb.ToString()); } #endregion #region Private Methods /// <summary> /// This function used to create the href attribute value of the A html tag. /// </summary> private string CreatePageHref(string text, int pageIndex) { //Check whether the client side turn page javascript function is null //If null, then we just return the text of the page item. if (string.IsNullOrEmpty(TurnPageClientFunction)) { return text; } return string.Format(pageHref, text, string.Format(turnPage, TurnPageClientFunction, pageIndex)); } /// <summary> /// This function used to render all the paging numbers. Like: 1,2,3,4,5 /// </summary> private string GetNumberPages() { int totalPages = TotalPages; int pageIndex = PageIndex; int pageLength = PageLength; //First, calculate the startIndex and endIndex. int startIndex = pageIndex - pageLength / 2; int endIndex = pageIndex + pageLength / 2; if (startIndex < 1) { endIndex += 1 - startIndex; startIndex = 1; } if (endIndex > totalPages) { startIndex -= endIndex - totalPages; endIndex = totalPages; } if (startIndex < 1) { startIndex = 1; } if (endIndex > totalPages) { endIndex = totalPages; } //Second, render all the paging numbers. StringBuilder sb = new StringBuilder(); for (int i = startIndex; i <= endIndex; i++) { if (pageIndex == i) { sb.Append("[" + i.ToString() + "]"); } else { sb.Append(CreatePageHref("[" + i.ToString() + "]", i)); } if (i < endIndex) { sb.Append(seperatorSpace); } } return sb.ToString(); } /// <summary> /// This function used to calculate the total pages. /// </summary> private int CalculateTotalPages(int totalRecords) { int totalPages; if (totalRecords == 0) { return 0; } totalPages = totalRecords / PageSize; if ((totalRecords % PageSize) > 0) { totalPages++; } return totalPages; } /// <summary> /// This function used to return a nullable integer value from the ViewState with the specified view state key. /// </summary> private int? GetNullableIntegerValue(string viewStateKey) { int? value = null; if (!string.IsNullOrEmpty(viewStateKey) && ViewState[viewStateKey] != null) { int tempValue = 0; if (int.TryParse(ViewState[viewStateKey].ToString(), out tempValue)) { value = tempValue; } } return value; } #endregion}