asp.net中让Repeater和GridView支持DataPager分页

改造办法是自己写一个控件，让它继承GridView或Repeater，并实现IPageableItemContainer 接口。下面要发的是国外某高手写的代码，测试有效。具体使用的时候，要建一个类库项目，把代码编译成dll后，就可以添加到VS的工具箱里了！
一、自定义Repeater

using System.Web.UI; 
using System.Web.UI.WebControls; 
namespace WYJ.Web.Controls 
{ 
/// <summary> 
/// Repeater with support for DataPager 
/// </summary> 
[ToolboxData("<{0}:DataPagerRepeater runat=server PersistentDataSource=true></{0}:DataPagerRepeater>")] 
public class DataPagerRepeater : Repeater, System.Web.UI.WebControls.IPageableItemContainer, INamingContainer 
{ 
/// <summary> 
/// Number of rows to show 
/// </summary> 
public int MaximumRows { get { return ViewState["MaximumRows"] != null ? (int)ViewState["MaximumRows"] : -1; } } 
/// <summary> 
/// First row to show 
/// </summary> 
public int StartRowIndex { get { return ViewState["StartRowIndex"] != null ? (int)ViewState["StartRowIndex"] : -1; } } 
/// <summary> 
/// Total rows. When PagingInDataSource is set to true you must get the total records from the datasource (without paging) at the FetchingData event 
/// When PagingInDataSource is set to true you also need to set this when you load the data the first time. 
/// </summary> 
public int TotalRows { get { return ViewState["TotalRows"] != null ? (int)ViewState["TotalRows"] : -1; } set { ViewState["TotalRows"] = value; } } 
/// <summary> 
/// If repeater should store data source in view state. If false you need to get and bind data at post back. When using a connected data source this is handled by the data source. 
/// </summary> 
public bool PersistentDataSource 
{ 
get { return ViewState["PersistentDataSource"] != null ? (bool)ViewState["PersistentDataSource"] : true; } 
set { ViewState["PersistentDataSource"] = value; } 
} 
/// <summary> 
/// Set to true if you want to handle paging in the data source. 
/// Ex if you are selecting data from the database and only select the current rows 
/// you must set this property to true and get and rebind data at the FetchingData event. 
/// If this is true you must also set the TotalRecords property at the FetchingData event. 
/// </summary> 
/// <seealso cref="FetchingData"/> 
/// <seealso cref="TotalRows"/> 
public bool PagingInDataSource 
{ 
get { return ViewState["PageingInDataSource"] != null ? (bool)ViewState["PageingInDataSource"] : false; } 
set { ViewState["PageingInDataSource"] = value; } 
} 
/// <summary> 
/// Checks if you need to rebind data source at postback 
/// </summary> 
public bool NeedsDataSource 
{ 
get 
{ 
if (PagingInDataSource) 
return true; 
if (IsBoundUsingDataSourceID == false && !Page.IsPostBack) 
return true; 
if (IsBoundUsingDataSourceID == false && PersistentDataSource == false && Page.IsPostBack) 
return true; 
else 
return false; 
} 
} 
/// <summary> 
/// Loading ViewState 
/// </summary> 
/// <param name="savedState"></param> 
protected override void LoadViewState(object savedState) 
{ 
base.LoadViewState(savedState); 
//if (Page.IsPostBack) 
//{ 
// if (!IsBoundUsingDataSourceID && PersistentDataSource && ViewState["DataSource"] != null) 
// { 
// this.DataSource = ViewState["DataSource"]; 
// this.DataBind(true); 
// } 
// if (IsBoundUsingDataSourceID) 
// { 
// this.DataBind(); 
// } 
//} 
} 
protected override void OnLoad(System.EventArgs e) 
{ 
if (Page.IsPostBack) 
{ 
if (NeedsDataSource && FetchingData != null) 
{ 
if (PagingInDataSource) 
{ 
SetPageProperties(StartRowIndex, MaximumRows, true); 
} 
FetchingData(this, null); 
} 
if (!IsBoundUsingDataSourceID && PersistentDataSource && ViewState["DataSource"] != null) 
{ 
this.DataSource = ViewState["DataSource"]; 
this.DataBind(); 
} 
if (IsBoundUsingDataSourceID) 
{ 
this.DataBind(); 
} 
} 
base.OnLoad(e); 
} 
/// <summary> 
/// Method used by pager to set totalrecords 
/// </summary> 
/// <param name="startRowIndex">startRowIndex</param> 
/// <param name="maximumRows">maximumRows</param> 
/// <param name="databind">databind</param> 
public void SetPageProperties(int startRowIndex, int maximumRows, bool databind) 
{ 
ViewState["StartRowIndex"] = startRowIndex; 
ViewState["MaximumRows"] = maximumRows; 
if (TotalRows > -1) 
{ 
if (TotalRowCountAvailable != null) 
{ 
TotalRowCountAvailable(this, new PageEventArgs((int)ViewState["StartRowIndex"], (int)ViewState["MaximumRows"], TotalRows)); 
} 
} 
} 
/// <summary> 
/// OnDataPropertyChanged 
/// </summary> 
protected override void OnDataPropertyChanged() 
{ 
if (MaximumRows != -1 || IsBoundUsingDataSourceID) 
{ 
this.RequiresDataBinding = true; 
} 
base.OnDataPropertyChanged(); 
} 
/// <summary> 
/// Renders only current items selected by pager 
/// </summary> 
/// <param name="writer"></param> 
protected override void RenderChildren(HtmlTextWriter writer) 
{ 
if (!PagingInDataSource && MaximumRows != -1) 
{ 
foreach (RepeaterItem item in this.Items) 
{ 
if (item.ItemType == ListItemType.Item || item.ItemType == ListItemType.AlternatingItem) 
{ 
item.Visible = false; 
if (item.ItemIndex >= (int)ViewState["StartRowIndex"] && item.ItemIndex < ((int)ViewState["StartRowIndex"] + (int)ViewState["MaximumRows"])) 
{ 
item.Visible = true; 
} 
} 
else 
{ 
item.Visible = true; 
} 
} 
} 
base.RenderChildren(writer); 
} 
/// <summary> 
/// Get Data 
/// </summary> 
/// <returns></returns> 
protected override System.Collections.IEnumerable GetData() 
{ 
System.Collections.IEnumerable dataObjects = base.GetData(); 
if (dataObjects == null && this.DataSource != null) 
{ 
if (this.DataSource is System.Collections.IEnumerable) 
dataObjects = (System.Collections.IEnumerable)this.DataSource; 
else 
dataObjects = ((System.ComponentModel.IListSource)this.DataSource).GetList(); 
} 
if (!PagingInDataSource && MaximumRows != -1 && dataObjects != null) 
{ 
int i = -1; 
if (dataObjects != null) 
{ 
i = 0; 
foreach (object o in dataObjects) 
{ 
i++; 
} 
} 
ViewState["TotalRows"] = i; 
if (!IsBoundUsingDataSourceID && PersistentDataSource) 
ViewState["DataSource"] = this.DataSource; 
SetPageProperties(StartRowIndex, MaximumRows, true); 
} 
if (PagingInDataSource && !Page.IsPostBack) 
{ 
SetPageProperties(StartRowIndex, MaximumRows, true); 
} 
return dataObjects; 
} 
/// <summary> 
/// Event when pager/repeater have counted total rows 
/// </summary> 
public event System.EventHandler<PageEventArgs> TotalRowCountAvailable; 
/// <summary> 
/// Event when repeater gets the data on postback 
/// </summary> 
public event System.EventHandler<PageEventArgs> FetchingData; 
} 
}

ASPX页面要做的事情（以我网站的留言板为例）：
首先得把标签注册进来

<%@ Register Assembly="WYJ.Web.Controls" Namespace="WYJ.Web.Controls" TagPrefix="WYJ" %>

然后添加我们的Repeater

<WYJ:DataPagerRepeater ID="rptLeaveword" runat="server" PersistentDataSource="true"> 
<ItemTemplate> 
<div class="leavewordentry"> 
<div class="datebox"> 
<div class="time"> 
<%# ((GeekStudio.ORM.Model.Leaveword)Container.DataItem).Posttime.ToString("HH:mm") %></div> 
<div class="day"> 
<%# ((GeekStudio.ORM.Model.Leaveword)Container.DataItem).Posttime.ToString("dd") %> 
</div> 
<div class="month"> 
<%# ((GeekStudio.ORM.Model.Leaveword)Container.DataItem).Posttime.ToString("MMM", new CultureInfo("en-US")).ToUpper() %><%# ((GeekStudio.ORM.Model.Leaveword)Container.DataItem).Posttime.ToString(" yyyy") %></div> 
</div> 
<div class="contentbox"> 
<h2 class="username"> 
<a id="<%# GeekStudio.Common.IdEncryptor.EncodeId(((GeekStudio.ORM.Model.Leaveword)Container.DataItem).Id) %>" 
name="<%# GeekStudio.Common.IdEncryptor.EncodeId(((GeekStudio.ORM.Model.Leaveword)Container.DataItem).Id) %>"> 
<%# ((GeekStudio.ORM.Model.Leaveword)Container.DataItem).Username %></a></h2> 
<div class="lvwordcontent"> 
<%# ((GeekStudio.ORM.Model.Leaveword)Container.DataItem).Content %> 
</div> 
</div> 
</div> 
</ItemTemplate> 
</WYJ:DataPagerRepeater>

之后添加.NET自带的DataPager，并自定义一些分页样式

<div class="pager"> 
<div class="fr"> 
共<%=Math.Ceiling((double)DataPager1.TotalRowCount / DataPager1.PageSize)%>页，<%=DataPager1.TotalRowCount%>条记录，每页显示 
<asp:LinkButton ID="lnkbtn10" CssClass="currentpagesize" runat="server" OnClick="lnkbtn10_Click">10</asp:LinkButton> 
<asp:LinkButton ID="lnkbtn20" runat="server" OnClick="lnkbtn20_Click">20</asp:LinkButton> 
<asp:LinkButton ID="lnkbtn30" runat="server" OnClick="lnkbtn30_Click">30</asp:LinkButton> 
</div> 
<asp:DataPager ID="DataPager1" PagedControlID="rptLeaveword" runat="server"> 
<Fields> 
<asp:NextPreviousPagerField ShowFirstPageButton="True" ShowNextPageButton="False" 
ShowPreviousPageButton="False" FirstPageText="首页" /> 
<asp:NextPreviousPagerField ShowNextPageButton="False" ButtonType="Image" PreviousPageImageUrl="~/Images/icons/pagerprevious.png" /> 
<asp:NumericPagerField CurrentPageLabelCssClass="current" /> 
<asp:NextPreviousPagerField ShowPreviousPageButton="False" ButtonType="Image" NextPageImageUrl="~/Images/icons/pagernext.png" /> 
<asp:NextPreviousPagerField ShowLastPageButton="True" ShowNextPageButton="False" 
ShowPreviousPageButton="False" LastPageText="尾页" /> 
</Fields> 
</asp:DataPager> 
</div>

后台代码：
分页部分不需要代码。下面发的代码是切换每页显示数量的：

protected void lnkbtn10_Click(object sender, EventArgs e) 
{ 
DataPager1.PageSize = 10; 
lnkbtn10.CssClass = "currentpagesize"; 
lnkbtn20.CssClass = ""; 
lnkbtn30.CssClass = ""; 
} 
protected void lnkbtn20_Click(object sender, EventArgs e) 
{ 
DataPager1.PageSize = 20; 
lnkbtn20.CssClass = "currentpagesize"; 
lnkbtn10.CssClass = ""; 
lnkbtn30.CssClass = ""; 
} 
protected void lnkbtn30_Click(object sender, EventArgs e) 
{ 
DataPager1.PageSize = 30; 
lnkbtn30.CssClass = "currentpagesize"; 
lnkbtn10.CssClass = ""; 
lnkbtn20.CssClass = ""; 
}

二、自定义GridView

using System; 
using System.Collections; 
using System.Web.UI.WebControls; 
namespace WYJ.Web.Controls 
{ 
/// <summary> 
/// DataPagerGridView is a custom control that implements GrieView and IPageableItemContainer 
/// </summary> 
public class DataPagerGridView : GridView, IPageableItemContainer 
{ 
public DataPagerGridView() 
: base() 
{ 
PagerSettings.Visible = false; 
} 
/// <summary> 
/// TotalRowCountAvailable event key 
/// </summary> 
private static readonly object EventTotalRowCountAvailable = new object(); 
/// <summary> 
/// Call base control's CreateChildControls method and determine the number of rows in the source 
/// then fire off the event with the derived data and then we return the original result. 
/// </summary> 
/// <param name="dataSource"></param> 
/// <param name="dataBinding"></param> 
/// <returns></returns> 
protected override int CreateChildControls(IEnumerable dataSource, bool dataBinding) 
{ 
int rows = base.CreateChildControls(dataSource, dataBinding); 
// if the paging feature is enabled, determine the total number of rows in the datasource 
if (this.AllowPaging) 
{ 
// if we are databinding, use the number of rows that were created, otherwise cast the datasource to an Collection and use that as the count 
int totalRowCount = dataBinding ? rows : ((ICollection)dataSource).Count; 
// raise the row count available event 
IPageableItemContainer pageableItemContainer = this as IPageableItemContainer; 
this.OnTotalRowCountAvailable(new PageEventArgs(pageableItemContainer.StartRowIndex, pageableItemContainer.MaximumRows, totalRowCount)); 
// make sure the top and bottom pager rows are not visible 
if (this.TopPagerRow != null) 
this.TopPagerRow.Visible = false; 
if (this.BottomPagerRow != null) 
this.BottomPagerRow.Visible = false; 
} 
return rows; 
} 
/// <summary> 
/// Set the control with appropriate parameters and bind to right chunk of data. 
/// </summary> 
/// <param name="startRowIndex"></param> 
/// <param name="maximumRows"></param> 
/// <param name="databind"></param> 
void IPageableItemContainer.SetPageProperties(int startRowIndex, int maximumRows, bool databind) 
{ 
int newPageIndex = (startRowIndex / maximumRows); 
this.PageSize = maximumRows; 
if (this.PageIndex != newPageIndex) 
{ 
bool isCanceled = false; 
if (databind) 
{ 
// create the event arguments and raise the event 
GridViewPageEventArgs args = new GridViewPageEventArgs(newPageIndex); 
this.OnPageIndexChanging(args); 
isCanceled = args.Cancel; 
newPageIndex = args.NewPageIndex; 
} 
// if the event wasn't cancelled change the paging values 
if (!isCanceled) 
{ 
this.PageIndex = newPageIndex; 
if (databind) 
this.OnPageIndexChanged(EventArgs.Empty); 
} 
if (databind) 
this.RequiresDataBinding = true; 
} 
} 
/// <summary> 
/// IPageableItemContainer's StartRowIndex = PageSize * PageIndex properties 
/// </summary> 
int IPageableItemContainer.StartRowIndex 
{ 
get { return this.PageSize * this.PageIndex; } 
} 
/// <summary> 
/// IPageableItemContainer's MaximumRows = PageSize property 
/// </summary> 
int IPageableItemContainer.MaximumRows 
{ 
get { return this.PageSize; } 
} 
/// <summary> 
/// 
/// </summary> 
event EventHandler<PageEventArgs> IPageableItemContainer.TotalRowCountAvailable 
{ 
add { base.Events.AddHandler(DataPagerGridView.EventTotalRowCountAvailable, value); } 
remove { base.Events.RemoveHandler(DataPagerGridView.EventTotalRowCountAvailable, value); } 
} 
/// <summary> 
/// 
/// </summary> 
/// <param name="e"></param> 
protected virtual void OnTotalRowCountAvailable(PageEventArgs e) 
{ 
EventHandler<PageEventArgs> handler = (EventHandler<PageEventArgs>)base.Events[DataPagerGridView.EventTotalRowCountAvailable]; 
if (handler != null) 
{ 
handler(this, e); 
} 
} 
} 
}

用法与Repeater类似，不多发了～