pager.cs

这是一个简单的论坛程序源码

using System;
using System.Text;
using System.Text.RegularExpressions;
using System.IO;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using NetFocus.Web.Core;

namespace NetFocus.Web.Applications.Forum 
{
	public class Pager : Label, IPagedControl, INamingContainer 
	{
		#region Member variables and constructor

        private WebContext csContext = WebContext.Current;
        private HyperLink previousLink;
        private HyperLink nextLink;
        private HyperLink firstLink;
        private HyperLink lastLink;
        private HyperLink[] pagingHyperLinks;

		public override ControlCollection Controls 
		{
			get 
			{
				EnsureChildControls();
				return base.Controls;
			}
		}
		protected override void CreateChildControls() 
		{
			Controls.Clear();

			// Add Page buttons
			//
			AddPageLinks();

			// Add Previous Next child controls
			//
			AddPreviousNextLinks();

			// Add First Last child controls
			//
			AddFirstLastLinks();

		}

		#endregion

		#region Render functions
		protected override void Render(HtmlTextWriter writer) 
		{

			int totalPages = TotalPages;

			// Do we have data?
			//
			if (totalPages <= 1)
				return;

			// Render the paging buttons
			//
			writer.AddAttribute(HtmlTextWriterAttribute.Class, this.CssClass, false);

			// Render the first button
			//
			RenderFirst(writer);

			// Render the previous button
			//
			RenderPrevious(writer);
            
			// Render the page button(s)
			//
			RenderPagingButtons(writer);

			// Render the next button
			//
			RenderNext(writer);

			// Render the last button
			//
			RenderLast(writer);

			//writer.RenderEndTag();

		}

		void RenderFirst (HtmlTextWriter writer) 
		{

			int totalPages = TotalPages;

			if ((PageIndex >= 3) && (totalPages > 5)) 
			{
				firstLink.RenderControl(writer);

				LiteralControl l = new LiteralControl("&nbsp;...&nbsp;");
				l.RenderControl(writer);
			}
		}

		void RenderLast (HtmlTextWriter writer) 
		{
			int totalPages = TotalPages;

			if (((PageIndex + 3) < totalPages) && (totalPages > 5)) 
			{
				LiteralControl l = new LiteralControl("&nbsp;...&nbsp;");
				l.RenderControl(writer);

				lastLink.RenderControl(writer);
			}

		}

		void RenderPrevious (HtmlTextWriter writer) 
		{
			Literal l;

			if (HasPrevious) 
			{
				previousLink.RenderControl(writer);

				l = new Literal();
				l.Text = "&nbsp;";
				l.RenderControl(writer);
			}

		}

		void RenderNext(HtmlTextWriter writer) 
		{
			Literal l;

			if (HasNext) 
			{

				l = new Literal();
				l.Text = "&nbsp;";
				l.RenderControl(writer);

				nextLink.RenderControl(writer);
			}

		}

		void RenderButtonRange(int start, int end, HtmlTextWriter writer) 
		{

			for (int i = start; i < end; i++) 
			{

				// Are we working with the selected index?
				//
				if (PageIndex == i) 
				{

					// Render different output
					//
					Literal l = new Literal();
					//l.Text = "<span class=\"currentPage\">[" + (i + 1).ToString() + "]</span>";
					l.Text = (i + 1).ToString();

					l.RenderControl(writer);
				} 
				else 
				{
                    pagingHyperLinks[i - start].RenderControl(writer);
				}
				if ( i < (end - 1) )
					writer.Write(" ");

			}

		}

		void RenderPagingButtons(HtmlTextWriter writer) 
		{
			int totalPages;

			// Get the total pages available
			//
			totalPages = TotalPages;

			// If we have <= 5 pages display all the pages and exit
			//
			if ( totalPages <= 5) 
			{
				RenderButtonRange(0, totalPages, writer);
			} 
			else 
			{

				int lowerBound = (PageIndex - 2);
				int upperBound = (PageIndex + 3);

				if (lowerBound <= 0) 
					lowerBound = 0;

				if (PageIndex == 0)
					RenderButtonRange(0, 5, writer);

				else if (PageIndex == 1)
					RenderButtonRange(0, (PageIndex + 4), writer);

				else if (PageIndex < (totalPages - 2))
					RenderButtonRange(lowerBound, (PageIndex + 3), writer);

				else if (PageIndex == (totalPages - 2))
					RenderButtonRange((totalPages - 5), (PageIndex + 2), writer);

				else if (PageIndex == (totalPages - 1))
					RenderButtonRange((totalPages - 5), (PageIndex + 1), writer);
			}
		}
		#endregion

		#region ControlTree functions
		void AddPageLinks() 
		{
            int lowerBound = (PageIndex - 2);
            int upperBound = (PageIndex + 3);

            if (lowerBound <= 0)
            {
                lowerBound = 0;
            }

            if (PageIndex == 0 || PageIndex == 1)
            {
                lowerBound = 0;
                upperBound = 5;
            }
            else if (PageIndex < (TotalPages - 2))
            {
                upperBound = PageIndex + 3;
            }
            else if (PageIndex == (TotalPages - 2))
            {
                lowerBound = TotalPages - 5;
                upperBound = PageIndex + 2;
            }
            else if (PageIndex == (TotalPages - 1))
            {
                lowerBound = TotalPages - 5;
                upperBound = PageIndex + 1;
            }
			// First add the lower page buttons
			//
            pagingHyperLinks = new HyperLink[upperBound - lowerBound];

			// Create the buttons and add them to 
			// the Controls collection
			//
            for (int i = lowerBound; i < upperBound; i++) 
			{
                pagingHyperLinks[i - lowerBound] = new HyperLink();
                pagingHyperLinks[i - lowerBound].EnableViewState = false;
                pagingHyperLinks[i - lowerBound].Text = (i + 1).ToString();
                pagingHyperLinks[i - lowerBound].ID = (i + 1).ToString();
                pagingHyperLinks[i - lowerBound].NavigateUrl = CreatePagerURL((i + 1).ToString());
                Controls.Add(pagingHyperLinks[i - lowerBound]);
			}
		}

		void AddFirstLastLinks() 
		{
			int start = 1;
			firstLink = new HyperLink();
			firstLink.ID = "First";
			firstLink.Text = Resources.GetString("Utility_Pager_firstButton");
			firstLink.NavigateUrl = CreatePagerURL(start.ToString());
			Controls.Add(firstLink);

			int last = TotalPages;
			lastLink = new HyperLink();
			lastLink.ID = "Last";
			lastLink.Text = Resources.GetString("Utility_Pager_lastButton");
			lastLink.NavigateUrl = CreatePagerURL(last.ToString());
			Controls.Add(lastLink);
		}

		void AddPreviousNextLinks() 
		{
			int previous;
			
			if (this.PageIndex < 2)
				previous = 1;
			else
				previous = this.PageIndex;

			previousLink = new HyperLink();
			previousLink.ID = "Prev";
			previousLink.Text = Resources.GetString("Utility_Pager_previousButton");
			previousLink.NavigateUrl = CreatePagerURL(previous.ToString());
			Controls.Add(previousLink);

			int next = this.PageIndex + 2;
			nextLink = new HyperLink();
			nextLink.ID = "Next";
			nextLink.Text = Resources.GetString("Utility_Pager_nextButton");
			nextLink.NavigateUrl = CreatePagerURL(next.ToString());
			Controls.Add(nextLink);
		}
		#endregion

		#region Private Properties
		private bool HasPrevious 
		{
			get 
			{
				if (PageIndex > 0)
					return true;

				return false;
			}
		}

		private bool HasNext 
		{
			get 
			{
				if (PageIndex + 1 < TotalPages )
					return true;

				return false;
			}
		}
		#endregion

		#region Helper methods and Public Properties
		protected virtual string CreatePagerURL(string pageIndex)
		{
			if(!string.IsNullOrEmpty(UrlPattern))
				return string.Format(UrlPattern,pageIndex);

            if (!string.IsNullOrEmpty(UrlName))
            {
                return UrlsData.Instance().FormatUrl(UrlName, new object[] { pageIndex });
            }

			if (csContext.CurrentUri.AbsoluteUri.IndexOf("?") == -1)
			{
				return csContext.CurrentUri.AbsoluteUri.ToString() + "?PageIndex=" + pageIndex;
			}
			else
			{
				if (csContext.CurrentUri.AbsoluteUri.IndexOf("PageIndex=") == -1)
					return csContext.CurrentUri.AbsoluteUri.ToString() + "&PageIndex=" + pageIndex;
				else
				{
					return Regex.Replace(csContext.CurrentUri.AbsoluteUri.ToString(), @"PageIndex=(\d+\.?\d*|\.\d+)", "PageIndex=" + pageIndex);
				}
			}
		}

		string _urlPattern = null;
		public string UrlPattern
		{
			get { return _urlPattern;}
			set {_urlPattern = value;}
		}

        string _urlName = null;
        public string UrlName
        {
            get { return _urlName; }
            set { _urlName = value; }
        }


		public virtual int CalculateTotalPages(int totalRecords) 
		{
			int totalPagesAvailable;

            if (totalRecords == 0)
				return 0;

			// First calculate the division
			//
            totalPagesAvailable = totalRecords / PageSize;

			// Now do a mod for any remainder
			//
            if ((totalRecords % PageSize) > 0)
				totalPagesAvailable++;

			return totalPagesAvailable;

		}

		
		int _pageIndex = 0;
		public virtual int PageIndex 
		{
			get 
			{
                // Give first try to the ViewState if it was a postback
                if (Page != null && Page.IsPostBack && ViewState["PageIndex"] != null){
                    _pageIndex = (int) ViewState["PageIndex"];
                }
                else {
                    if (csContext.QueryString["pageindex"] != null)
                        _pageIndex = int.Parse(csContext.QueryString["pageindex"]) - 1;
                }

				if (_pageIndex < 0)
					return 0;
				else
					return _pageIndex;
			}
			set 
			{
				ViewState["PageIndex"] = value;
				_pageIndex = value;
			}
		}

		public virtual int PageSize 
		{
			get 
			{
				int pageSize = Convert.ToInt32(ViewState["PageSize"]);

				if (pageSize == 0) 
					return 10;

				return pageSize;
			}
			set 
			{
				ViewState["PageSize"] = value;
			}

		}

		private bool _causeValidation = true;
		public bool CausesValidation
		{
			get {return _causeValidation;}
			set {_causeValidation = value;}
		}

        public int TotalPages
        {
            get
            {
                return Convert.ToInt32(ViewState["TotalPages"]);
            }
            set
            {
                ViewState["TotalPages"] = value;
            }
        }

		public string UrlCleaner(string RawURL, string QueryName)
		{
			// Configure the Url
			if(RawURL.IndexOf("?") != -1)
			{
				bool hasPart = false;
				string queryString = RawURL.Substring( RawURL.IndexOf("?") + 1 );
				string[] parts = queryString.Split('&');
				for(int i = 0 ; i < parts.Length ; i++)
				{
					if(parts[i].StartsWith(QueryName))
					{
						parts[i] = QueryName + "={0}";
						hasPart = true;
					}
				}
				if(hasPart == true)
					RawURL = RawURL.Replace(queryString, string.Join("&", parts));
				else
					RawURL = RawURL.Replace(queryString, string.Join("&", parts) + "&" + QueryName + "={0}");
			}
			else
				RawURL = RawURL + "?" + QueryName + "={0}";

			return RawURL;

		}

		#endregion

	}
}