【下载文档:  asp.net中让Repeater和GridView支持DataPager分页.txt 】

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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 复制代码 代码如下: using System.Web.UI; using System.Web.UI.WebControls; namespace WYJ.Web.Controls { ///

/// Repeater with support for DataPager ///

[ToolboxData("<{0}:DataPagerRepeater runat=server PersistentDataSource=true>")] public class DataPagerRepeater : Repeater, System.Web.UI.WebControls.IPageableItemContainer, INamingContainer { ///

/// Number of rows to show ///

public int MaximumRows { get { return ViewState["MaximumRows"] != null ? (int)ViewState["MaximumRows"] : -1; } } ///

/// First row to show ///

public int StartRowIndex { get { return ViewState["StartRowIndex"] != null ? (int)ViewState["StartRowIndex"] : -1; } } ///

/// 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. ///

public int TotalRows { get { return ViewState["TotalRows"] != null ? (int)ViewState["TotalRows"] : -1; } set { ViewState["TotalRows"] = value; } } ///

/// 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. ///

public bool PersistentDataSource { get { return ViewState["PersistentDataSource"] != null ? (bool)ViewState["PersistentDataSource"] : true; } set { ViewState["PersistentDataSource"] = value; } } ///

/// 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. ///

/// /// public bool PagingInDataSource { get { return ViewState["PageingInDataSource"] != null ? (bool)ViewState["PageingInDataSource"] : false; } set { ViewState["PageingInDataSource"] = value; } } ///

/// Checks if you need to rebind data source at postback ///

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; } } ///

/// Loading ViewState ///

/// 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); } ///

/// Method used by pager to set totalrecords ///

/// startRowIndex /// maximumRows /// databind 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)); } } } ///

/// OnDataPropertyChanged ///

protected override void OnDataPropertyChanged() { if (MaximumRows != -1 || IsBoundUsingDataSourceID) { this.RequiresDataBinding = true; } base.OnDataPropertyChanged(); } ///

/// Renders only current items selected by pager ///

/// 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); } ///

/// Get Data ///

/// 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; } ///

/// Event when pager/repeater have counted total rows ///

public event System.EventHandler TotalRowCountAvailable; ///

/// Event when repeater gets the data on postback ///

public event System.EventHandler 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 复制代码 代码如下:<%@ Register Assembly="WYJ.Web.Controls" Namespace="WYJ.Web.Controls" TagPrefix="WYJ" %> 然后添加我们的Repeater 复制代码 代码如下:

<%# ((GeekStudio.ORM.Model.Leaveword)Container.DataItem).Posttime.ToString("HH:mm") %>

<%# ((GeekStudio.ORM.Model.Leaveword)Container.DataItem).Posttime.ToString("dd") %>

<%# ((GeekStudio.ORM.Model.Leaveword)Container.DataItem).Posttime.ToString("MMM", new CultureInfo("en-US")).ToUpper() %><%# ((GeekStudio.ORM.Model.Leaveword)Container.DataItem).Posttime.ToString(" yyyy") %>

<%# ((GeekStudio.ORM.Model.Leaveword)Container.DataItem).Username %>

<%# ((GeekStudio.ORM.Model.Leaveword)Container.DataItem).Content %>

之后添加.NET自带的DataPager，并自定义一些分页样式 复制代码 代码如下:

共<%=Math.Ceiling((double)DataPager1.TotalRowCount / DataPager1.PageSize)%>页，<%=DataPager1.TotalRowCount%>条记录，每页显示 10 20 30

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： 复制代码 代码如下: 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 复制代码 代码如下: using System; using System.Collections; using System.Web.UI.WebControls; namespace WYJ.Web.Controls { ///

/// DataPagerGridView is a custom control that implements GrieView and IPageableItemContainer ///

public class DataPagerGridView : GridView, IPageableItemContainer { public DataPagerGridView() : base() { PagerSettings.Visible = false; } ///

/// TotalRowCountAvailable event key ///

private static readonly object EventTotalRowCountAvailable = new object(); ///

/// 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. ///

/// /// /// 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; } ///

/// Set the control with appropriate parameters and bind to right chunk of data. ///

/// /// /// 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; } } ///

/// IPageableItemContainer's StartRowIndex = PageSize * PageIndex properties ///

int IPageableItemContainer.StartRowIndex { get { return this.PageSize * this.PageIndex; } } ///

/// IPageableItemContainer's MaximumRows = PageSize property ///

int IPageableItemContainer.MaximumRows { get { return this.PageSize; } } ///

/// ///

event EventHandler IPageableItemContainer.TotalRowCountAvailable { add { base.Events.AddHandler(DataPagerGridView.EventTotalRowCountAvailable, value); } remove { base.Events.RemoveHandler(DataPagerGridView.EventTotalRowCountAvailable, value); } } ///

/// ///

/// protected virtual void OnTotalRowCountAvailable(PageEventArgs e) { EventHandler handler = (EventHandler)base.Events[DataPagerGridView.EventTotalRowCountAvailable]; if (handler != null) { handler(this, e); } } } } 用法与Repeater类似，不多发了～