.NET 3.5中的DataPager碉堡了,可惜只支持ListView。传统的GridView和Repeater都无法直接使用DataPager分页。但我们如果稍加改造,就可以让Repeater和GridView支持DataPager分页。本网站的博客和留言板就是用Repeater+DataPager做的分页。

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~