votingcontrol.cs

一个ASP.NET下的中文内容管理和社区系统

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Web;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using ASPNET.StarterKit.Communities;


namespace ASPNET.StarterKit.Communities {
	/// <summary>
	/// The Vote control is allows for users to vote on topics. The results are stored in 
	/// a SQL Server table and a HTML graph is used to display the selections/percentages.
	/// 
	/// Adopted from Rob Howard's ([e-mail]) Voting Control.
	/// </summary>
	public class VotingControl : WebControl, System.Web.UI.INamingContainer {
		// Internal members
		//
		RadioButtonList radioButtonList;
		PollDetails polldetails;
		System.Drawing.Color barBackColor = System.Drawing.Color.LightGray;
		System.Drawing.Color barForeColor = System.Drawing.Color.Blue;
		Style questionStyle;
		Style itemStyle;
		Style buttonStyle;
		string buttonText = "Vote";
		int section_ID;
		string userName;
		
		protected override void OnLoad(EventArgs e) {
			//InitializeControl();
		}

		private void InitializeControl() {
			// Try to get user and page information if available
			if (HttpContext.Current.Items["UserInfo"]!=null) {
				UserInfo userInfo = (UserInfo)HttpContext.Current.Items["UserInfo"];
				userName=userInfo.Username;
			} else {
				userName=String.Empty;
			}
			if (HttpContext.Current.Items["SectionInfo"]!=null) {
				SectionInfo objSectionInfo =(SectionInfo)HttpContext.Current.Items["SectionInfo"];
				section_ID = objSectionInfo.ID;
			} else {
				section_ID=0;
			}

			// Get Poll Details 
			//
			polldetails = GetPollDetails();
		}

		
		/// <summary>
		/// Used to indicate whether multiple votes are allowed per user. Default is false.
		/// </summary>
		public bool AllowMultipleVote=false;

		/// <summary>
		/// Controls the height of the control
		/// </summary>
		public override Unit Height {
			get {
				return base.Height;
			}
			set {
				base.Height = value;
			}
		}

		/// <summary>
		/// Controls the width of the control
		/// </summary>
		public override Unit Width {
			get {
				return base.Width;
			}
			set {
				base.Width = value;
			}
		}

		/// <summary>
		/// Used to control the text on the button. Default is 'Vote'
		/// </summary>
		public String ButtonText {
			get {
				return buttonText;
			}
			set {
				buttonText = value;
			}
		}

		/// <summary>
		/// Sets the style for the question
		/// </summary>
		public Style QuestionStyle {
			get {
				if (questionStyle == null)
					questionStyle = new Style();

				return questionStyle;
			}
		}

		/// <summary>
		/// Sets the general style for displayed items
		/// </summary>
		public Style ItemStyle {
			get {
				if (itemStyle == null)
					itemStyle = new Style();
					
				return itemStyle;
			}
		}

		/// <summary>
		/// Sets the style for the button used in voting
		/// </summary>
		public Style ButtonStyle {
			get {
				if (buttonStyle == null)
					buttonStyle = new Style();
					
				return buttonStyle;
			}
		}

		/// <summary>
		/// Override control collection and return base collection
		/// </summary>
		public override ControlCollection Controls {
			get {
				EnsureChildControls();
				return base.Controls;
			}
		}

		/// <summary>
		/// Controls the back ground color of the rendered bar(s).
		/// </summary>
		public System.Drawing.Color BarBackColor {
			get {
				return barBackColor;
			}
			set {
				barBackColor = value;
			}
		}

		/// <summary>
		/// Controls the foreground color of the rendered bar(s).
		/// </summary>
		public System.Drawing.Color BarForeColor {
			get {
				return barForeColor;
			}
			set {
				barForeColor = value;
			}
		}
		
		protected override void CreateChildControls() {
			InitializeControl();
			// There may not be a poll available for this page
			if (polldetails!=null) {
				if (CheckHasVoted())
					HasVoted();
				else
					HasNotVoted();
			}
		}

		protected void HasNotVoted() {
			// Member variables
			//
			Table t = new Table();
			TableRow questionRow = new TableRow();
			TableRow choicesRow = new TableRow();
			TableRow buttonRow = new TableRow();
			TableCell questionCell = new TableCell();
			TableCell choicesCell = new TableCell();
			TableCell buttonCell = new TableCell();
			Button button = new Button();
			radioButtonList = new RadioButtonList();
			
			// Wire up the button click event
			//
			button.Click += new EventHandler(VoteButtonClick);
			
			
			// Format Question
			//
			questionCell.Text = polldetails.Question;
			questionRow.ControlStyle.CopyFrom(questionStyle);

			// Insert question cell and row into table
			//
			questionRow.Cells.Add(questionCell);
			t.Rows.Add(questionRow);

			// Format Radio Button
			//
			radioButtonList.ControlStyle.CopyFrom(itemStyle);

			// Populate the radioButtonList
			//
			foreach (ChoiceInfo choice in polldetails.Choices.OrderedChoices) 
				radioButtonList.Items.Add(new ListItem(choice.Choice,choice.PollChoice_ID.ToString()));
			// Insert the radio button into the cell
			//
			choicesCell.Controls.Add(radioButtonList);

			// Add row/cell to table
			//
			choicesRow.Cells.Add(choicesCell);
			t.Rows.Add(choicesRow);

			// Format Button
			//
			button.Text = buttonText;
			button.ControlStyle.CopyFrom(buttonStyle);

			// Insert button into cell
			//
			buttonCell.Controls.Add(button);

			// Add button cell/row to table
			//
			buttonRow.Cells.Add(buttonCell);
			t.Rows.Add(buttonRow);

			// Add table to the controls collection
			//
			this.Controls.Add(t);
			this.Controls.Add(new LiteralControl("<p>"));

		}

		protected void VoteButtonClick(Object sender, EventArgs e) {
			HttpContext.Current.Trace.Write("VoteButtonClick");
			if (radioButtonList.SelectedIndex!=-1) {
				int pollChoice_ID=Int32.Parse(radioButtonList.SelectedItem.Value);
				// Cast vote and save in DB
				VotingUtility.CreatePollResult(userName,pollChoice_ID);
				// Make cookie aware that this user has voted for this poll.
				AddPollToCookie();
			
				this.Controls.Clear();	
				
				HasVoted();
			}
		}

		protected void HasVoted() {
			// Member Variables
			//
			Table t = new Table();
			TableRow questionRow = new TableRow();
			TableRow resultsRow = new TableRow();
			TableRow footerRow = new TableRow();
			TableCell questionCell = new TableCell();
			TableCell resultsCell = new TableCell();
			TableCell footer = new TableCell();

			// Format the table
			//
			t.BorderWidth = 0;

			// Question
			//
			questionCell.Text = polldetails.Question;
			questionCell.ColumnSpan = 3;
			questionCell.ControlStyle.CopyFrom(questionStyle);

	
			// Add the question cell/row to the table
			//
			questionRow.Cells.Add(questionCell);
			t.Rows.Add(questionRow);

			if (polldetails.DisplayResultsToPublic) {
				Hashtable pollresults = VotingUtility.GetPollResults(polldetails.Poll_ID);

				// Calculate the sum
				//
				int sum=0;
				
				foreach (int key in pollresults.Keys)
					sum = sum + (int)pollresults[key];
				
				// Calculate percentage
				//
				foreach (int key in pollresults.Keys) {
					// Internal variables/instances
					//
					double d = 0;
					TableRow row = new TableRow();
					TableCell progressCell = new TableCell();
					TableCell percentageCell = new TableCell();
					TableCell choiceCell = new TableCell();
					ProgressBar bar = new ProgressBar();
				
					// Percentage for this poll value
					//
					d = ((double)((int)pollresults[key]) / (double)sum) * 100;

					// Display the choice in cell and format
					//
					choiceCell.Text = ((ChoiceInfo)polldetails.Choices[key]).Choice + ": ";
					choiceCell.VerticalAlign = VerticalAlign.Top;
					choiceCell.ControlStyle.CopyFrom(itemStyle);
					choiceCell.Wrap = false;

					// Set properties for each bar
					//
					bar.PercentageOfProgress = (int)d;
					bar.BackColor = this.BarBackColor;
					bar.ForeColor = this.BarForeColor;

					// Add the bar and set properties of the cell
					//
					progressCell.Controls.Add(bar);
					progressCell.HorizontalAlign = HorizontalAlign.Right;
					progressCell.VerticalAlign = VerticalAlign.Top;
					progressCell.Width = 100;

					// Special case 0
					//
					if ((double.IsNaN(d)) || (0 == d))
						percentageCell.Text = "(0%)";
					else
						percentageCell.Text = "(" + d.ToString("##.#") + "%)";

					// Format percentage cell
					//
					percentageCell.HorizontalAlign = HorizontalAlign.Left;
					percentageCell.VerticalAlign = VerticalAlign.Top;
					percentageCell.ControlStyle.CopyFrom(itemStyle);

					// Add the cells to the row
					//
					row.Cells.Add(choiceCell);
					row.Cells.Add(progressCell);
					row.Cells.Add(percentageCell);

					// Add the row to the table
					//
					t.Rows.Add(row);
					
				}
			}

			// What you voted for
			// 
			resultsCell.ColumnSpan = 3;
			resultsCell.HorizontalAlign = HorizontalAlign.Right;
			resultsCell.ControlStyle.CopyFrom(itemStyle);
			// Get Users data from the database
			// TODO: Rethink cookie design to store Anonymous user's values.
			if (userName!=String.Empty && userName!="Anonymous") {
				resultsCell.Text = "Your vote: " + VotingUtility.GetUsersChoice(polldetails.Poll_ID,userName).Choice;
			} else {
				resultsCell.Text = "You have already voted for this poll.";
			}

			// Add results cell/row to table
			//
			resultsRow.Cells.Add(resultsCell);
			t.Rows.Add(resultsRow);
			
			this.Controls.Add(t);
            this.Controls.Add(new LiteralControl("<p>"));
		}

		// Cache poll details in the ViewState. 
		private PollDetails GetPollDetails() {
			PollDetails pollDetails;
			// Maintain the same Poll_ID accross postbacks
			if (ViewState["Poll_ID"]==null) {
				pollDetails = VotingUtility.GetPollForWebBox(CommunityGlobals.CommunityID,section_ID,userName);
				if (pollDetails!=null)
					ViewState["Poll_ID"]=pollDetails.Poll_ID;
			} else {
				pollDetails = VotingUtility.GetPollForWebBox((int)ViewState["Poll_ID"]);
			}
			return pollDetails;
		}
		

		// Checks if the user has already voted. 
		private bool CheckHasVoted() {
			HttpCookie cookie = GetCookie();
			bool hasVoted=false;
			// First, check cookie
			if (cookie.Value.Length>0) {
				string[] polls=cookie.Value.Split('|');
				foreach (string poll in polls) {
					if (poll==polldetails.Poll_ID.ToString()) {
						hasVoted=true;
						break;
					}
				}
			}
			// Check DB
			if (!hasVoted && userName.Length>0) {
				ChoiceInfo choice = VotingUtility.GetUsersChoice(polldetails.Poll_ID,userName);
				if (choice.PollChoice_ID!=0) {
					hasVoted=true;
				}
			}
			return hasVoted;
		}

		// Adds this poll to the "voted" cookie.
		private void AddPollToCookie() {
			HttpCookie cookie = GetCookie();
			if (cookie.Value.Length==0)
				cookie.Value=polldetails.Poll_ID.ToString();
			else
				cookie.Value=cookie.Value+"|" + polldetails.Poll_ID.ToString();
			HttpContext.Current.Response.Cookies.Add(cookie);
		}

		// Retrieves the cookie and creates a new one if it doesn't exist.
		private HttpCookie GetCookie() {
			string cookieName="AspNetCommunityVoting_" + userName;
			HttpCookie cookie = HttpContext.Current.Request.Cookies[cookieName];
			if (cookie==null) {
				HttpContext.Current.Response.Cookies.Add(new HttpCookie(cookieName,String.Empty));
				cookie = HttpContext.Current.Response.Cookies[cookieName];
				cookie.Expires=DateTime.MaxValue;
			}
			return cookie;
		}
	}
}