Displaying Poll Results in Kentico


I’m pretty sure an hour after the first website launched in 1991, someone put a poll up asking people a profound question to get their opinions. Since then, polls have continued to be a great way to get a feel for how your users like a product, enjoyed an event, or any other type of survey. Kentico has a built-in poll module that allows you to place polls on your site easily and get feedback from your users. In this blog, I’ll show you how, with a little bit of JavaScript and API code, you can display poll results anywhere.

Recently, we have started putting a poll up every Friday on DevNet. The topics range from programming to community-based ones and give us great insight into our users. While these results are easily viewable from within the Poll Module (or after voting), I wanted to see what it would take to display the data a little more graphically. Specifically, I thought it might be nice to display a pie chart of the votes for each poll.

1. Creating a new web part

The first step of the process was to create a new Poll Chart web part. Nothing special here, just a basic web part with a blank layout.

Basic Webpart

You can find instructions on creating custom web parts here.

2. Choosing a charting control

There are a lot of options when it comes to charting libraries and controls, so you can’t go wrong with any of them. As long as you can submit data easily and logically, it’s up to you to decide which method is best. For my demo, I chose HighchartsJS. It’s a nice, well-documented library with a lot of great features.

I followed the installation instructions here, and added the following to the top of my web part:

<script src="http://code.highcharts.com/highcharts.js"></script> <script src="https://code.highcharts.com/modules/exporting.js"></script>

These libraries would pull in the Highcharts.js functionality from their CDN.

3. Adding a basic chart

After adding the JS libraries, I added a basic chart and set some properties. Note that I added some C# code to the layout for the values I will be setting in the code behind.

<script> $(function () { // Radialize the colors Highcharts.getOptions().colors = Highcharts.map(Highcharts.getOptions().colors, function (color) { return { radialGradient: { cx: 0.5, cy: 0.3, r: 0.7 }, stops: [ [0, color], [1, Highcharts.Color(color).brighten(-0.3).get('rgb')] // darken ] }; }); $('#pollcontainer').highcharts({ chart: { plotBackgroundColor: null, plotBorderWidth: null, plotShadow: false, type: 'pie' }, title: { text: '<%= strPollName%>' }, tooltip: { pointFormat: '{series.name}: <b>{point.percentage:.1f}%</b>' }, plotOptions: { pie: { allowPointSelect: true, cursor: 'pointer', dataLabels: { enabled: true, formatter: function () { if (this.point.name.length > 20) { return '<b>' + this.point.name.substring(0, 15) + '...</b> : ' + Highcharts.numberFormat(this.percentage, 1) + ' %'; } else { return '<b>' + this.point.name + '</b> : ' + Highcharts.numberFormat(this.percentage, 1) + ' %'; } }, style: { color: (Highcharts.theme && Highcharts.theme.contrastTextColor) || 'black' }, connectorColor: 'silver' }, showInLegend: <%= blnShowLegend.ToString().ToLower()%> } }, series: [{ name: 'Votes', colorByPoint: true, data: [<%= strPollAnswers%>] }] }); }); </script>

4. Getting the poll data

As part of my web part, I added a property that would allow me to select the poll I wanted to display. I also added another setting which will determine if the legend should be displayed.

#region "Properties" /// <summary> /// Gets / Sets the poll to chart /// </summary> public string PollCodeName { get { return ValidationHelper.GetString(GetValue("PollCodeName"), ""); } set { SetValue("PollCodeName", value); } } /// Determines whether the legend is displaed /// </summary> public bool PollShowLegend { get { return ValidationHelper.GetBoolean(GetValue("PollShowLegend"), false); } set { SetValue("PollShowLegend", value); } } #endregion

In my web part code-behind, I use the PollInfoProvider API to get the selected poll data.

// Get the poll information PollInfo poll = PollInfoProvider.GetPollInfo(this.PollCodeName, CurrentSite.SiteID); if (poll != null) { strPollName = poll.PollQuestion; ... }

Next, I get all of the answers for the poll. I also used the System.Data.DataTable.Compute function to get the total number of votes for the poll.

// Gets the poll's answers InfoDataSet<PollAnswerInfo> pollanswers = PollAnswerInfoProvider.GetAnswers(poll.PollID); // Get the total number of answers for the poll int intAnswerCount = ValidationHelper.GetInteger(pollanswers.Tables[0].Compute("Sum(AnswerCount)", ""), 0);

Lastly, I looped through each of the poll answers and calculated the percentage. This, along with the AnswerText, was passed to the Highcharts.JS library as the Series data.

if (intAnswerCount > 0) { var list = new List<string>(); // Loops through individual poll answers foreach (PollAnswerInfo pollanswer in pollanswers) { list.Add("{name: '" + pollanswer.AnswerText + "',y:" + Math.Round(ValidationHelper.GetDouble((ValidationHelper.GetDouble(pollanswer.AnswerCount, 0) / ValidationHelper.GetDouble(intAnswerCount, 0)) * 100, 0), 2) + "}"); } // Set the chart series data strPollAnswers = String.Join(",", list.ToArray()); }

5. Testing

With that code in place, I was ready to test. I added the web part to a page and set the poll I wanted to display.

Add Webpart

After that, I viewed the live site.

Working Chart 1

I then updated my web part to display the legend and confirmed it displayed correctly.

Working Chart 2

Moving Forward

Working charts in Kentico is a pretty easy task that can add some great UI and graphics to your site. I recommend checking out other charting libraries and controls to see which one fits your needs the best. Good luck!

Get the code

Exported web part

This blog is intended for informational purposes only and provides an example of one of the many ways to accomplish the described task. Always consult Kentico Documentation for the best practices and additional examples that may be more effective in your specific situation.

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Bryan Soltis

Hello. I am a Technical Evangelist here at Kentico and will be helping the technical community by providing guidance and best practices for all areas of the product. I might also do some karaoke. We'll see how it the night goes...