How to elegantly plot charts in ASP.NET MVC 3 using Highcharts? - json

Question

I've been working with highcharts and MVC 3 for two years by now (I never done anything complicated, just load data and make it work stuff), and I worked with two different scenarios:
Chart code written in the directly in the view, loading data through Json
Html helper responsible to plot the chart
The Html helper approach seems to me a more elegant choice ... but then, just to illustrate to you guys, here is how it looks like (just part of it):
public static string DisplayChart(
this HtmlHelper helper,
ChartOptions options,
TimedChartSeries[] data)
{
string[] axisList = data.GroupBy(t => t.Unit).Select(t => t.Key).ToArray();
string result = "";
result += "<script type=\"text/javascript\">\n";
result += "var " + options.ChartName + ";\n";
result += "$(document).ready(function() {\n";
result += options.ChartName + "= new Highcharts.Chart({\n";
result += "chart: {renderTo: '" + options.DivName + "',zoomType: ''},\n";
result += "title: { text: '" + options.Title + "'},\n";
result += "subtitle: {text: '" + options.SubTitle + "'},\n";
result += "xAxis: { type: 'datetime'," +
"\n dateTimeLabelFormats: {month: '%e. %b', year: '%b' },"
+ "labels:{rotation: -45}\n},\n";
string axes = "";
for (int i = 0; i < axisList.Length; i++)
{
var temporaryData = data.First(t => t.Unit == axisList[i]);
if (i != 0)
axes += ", ";
axes += "{labels:{\n " +
"formatter : function(){return this.value + '" + temporaryData.Unit + "';},\n" +
"style:{color:'#" + temporaryData.Color.Name.Remove(0, 2) + "'}},\n" +
"title:{text:'',style:{color:'#" + temporaryData.Color.Name.Remove(0, 2) + "'}},\n" +
"}\n";
}
result += "yAxis: [\n" + axes + "],\n";
string units = "";
for (int i = 0; i < data.Length; i++)
{
if (i != 0)
units += ", ";
units += "'" + data[i].Title + "': '" + data[i].Unit + "'\n";
}
result += "tooltip:{\nshared: true,\n backgroundColor: 'none' ,\nborderColor: 'none'," +
"\nshadow:false\n ,crosshairs: true,\n" +
"formatter: function() {var s = '<table class=\"table-list\"><tr><th>Hora</th><th>'+ test(this.x) +'</th></tr>';" +
"\n$.each(this.points, function(i, point) {" +
"\ns += '<tr><td>'+point.series.name + '</td><td>'+point.y+'</td></tr>'});s+='</table>';" +
"\n$('#tooltip').html(s);}},";
result += "lang: {" +
"months: ['Janeiro', 'Fevereiro', 'Março', 'Abril', 'Maio', 'Junho'," +
"'Julho', 'Agosto', 'Setembro', 'Outubro', 'Novembro', 'Dezembro']," +
"weekdays: ['Domingo', 'Segunda', 'Terça', 'Quarta', 'Quinta', 'Sexta', 'Sábado']},";
string series = "";
int x = 0;
for (int j = 0; j < axisList.Length; j++)
{
var temporaryData = data.Where(t => t.Unit == axisList[j]).ToArray();
for (int i = 0; i < temporaryData.Length; i++)
{
if (x > 0)
series += ", ";
series += "{name: '" + temporaryData[i].Title + "',\n color: '#" + temporaryData[i].Color.Name.Remove(0, 2) +
"', \ntype: '" + temporaryData[i].Type + "',\nunit:'" + temporaryData.First().Unit + "', \nyAxis:" + j + " , \ndata:[" + FromArrayToString(temporaryData[i].Data) +
"], marker: { enabled: false}}\n";
x++;
}
}
result += "series: [\n" + series + "]\n";
result += "});});";
result += "\nfunction test(i)\n{\nvar j = new Date(i + 2*60*60*1000);\n" +
"return new Date(i + 3*60*60*1000).format('d/m/Y H:i:s.')+j.getMilliseconds();\n}\n</script>";
result += "\n<div id=\"" + options.DivName + "\" style=\"width:" + options.Width + ";height: " + options.Height + "\"></div>" +
"<div id=\"tooltip\"></div>";
return result;
}
It's really simple to call this helper:
#Html.Raw(Html.DisplayChart((ChartOptions)Model.Options,(TimedChartSeries[])Model.Series))
As you guys can see, I have to use the Html.Raw helper in order to make it work ... that is problem nº 1 (and it probably has an easy solution). But the second problem is really great: the chart becomes entirely tied to my domain. If I wanted to plot a, say, bar chart displaying data of the last 3 years in months (each month being represented by a bar), it would be impossible to use this helper.
And it also looks kind of ugly.
So, guys, which option do you think is more elegant, the Json or the Helper approach?

Answer 1

About the use of Html.Raw and the easy solution:
Change your function to
public static HtmlString DisplayChart(this HtmlHelper helper, ...)
{
...
return new HtmlString(result);
}
You then may use #Html.DisplayChart(...) in your razor views.
Also, please make sure that options.DivName, options.Title, options.SubTitle etc. are properly escaped - a title like Everybody's favorite chart will break the output.