我正在尝试使用Google 图表 API在我的网站中显示一个饼图,到目前为止我无法让它工作,我找不到任何使用 MVC 3 Razor的示例。
这是我使用 json 获取数据的代码
// Load the Visualization API and the piechart package.
google.load('visualization', '1.0', { 'packages': ['corechart'] });
// Set a callback to run when the Google Visualization API is loaded.
google.setOnLoadCallback(drawChart);
JSON.stringify = JSON.stringify || function (obj) {
var t = typeof (obj);
if (t != "object" || obj === null) {
// simple data type
if (t == "string") obj = '"' + obj + '"';
return String(obj);
}
else {
// recurse array or object
var n, v, json = [], arr = (obj && obj.constructor == Array);
for (n in obj) {
v = obj[n]; t = typeof (v);
if (t == "string") v = '"' + v + '"';
else if (t == "object" && v !== null) v = JSON.stringify(v);
json.push((arr ? "" : '"' + n + '":') + String(v));
}
return (arr ? "[" : "{") + String(json) + (arr ? "]" : "}");
}
};
// Callback that creates and populates a data table,
// instantiates the pie chart, passes in the data and
// draws it.
function drawChart() {
// Create the data table.
var data = new google.visualization.DataTable();
data.addColumn('string', 'Topping');
data.addColumn('number', 'Slices');
$.post('@Url.Content("~/Home/GetMyChart1")',
function (items) {
// Successful requests get here
alert(JSON.stringify(items) + " - " + items.rows.length);
data.addRows(items.rows.length);
$.each(items.rows, function (i, item) {
alert(i);
data.setCell(i, 0, item.Name);
data.setCell(i, 1, item.ID);
});
alert("finished");
alert(data.length);
});
// Set chart options
var options = { 'title': 'How Much Pizza I Ate Last Night',
'width': 400,
'height': 300
};
// Instantiate and draw our chart, passing in some options.
var chart = new google.visualization.PieChart(document.getElementById('chart_div'));
chart.draw(data, options);
}
控制器代码
public ActionResult GetMyChart1(string CurrentClass)
{
var tests = from t in db.Tests
group t by new { t.StudentID, t.Student.CurrentSchoolGrade } into tl
select new { StudentID = tl.Key.StudentID, Class = tl.Key.CurrentSchoolGrade, Score = (tl.Sum(k => k.Score)/tl.Sum(l => l.Part.Score))* 100, Count = tl.Count() };
var results = from t in tests
where t.Class == CurrentClass
select t;
List<DataItem> dt = new List<DataItem>();
dt.Add(new DataItem(results.Count(x => x.Score <= 40), "0% - 40%"));
dt.Add(new DataItem(results.Count(x => x.Score <= 60 && x.Score > 40), "40% - 60%"));
dt.Add(new DataItem(results.Count(x => x.Score <= 80 && x.Score > 60), "60% - 80%"));
dt.Add(new DataItem(results.Count(x => x.Score <= 100 && x.Score > 60), "80% - 100%"));
chartJson cj = new chartJson();
cj.rows = dt;
return Json(cj);
}
public class chartJson
{
public List<DataItem> rows { get; set; }
}
public class DataItem
{
public DataItem(int id, string name)
{
ID = id;
Name = name;
}
public int ID { get; set; }
public string Name { get; set; }
}
除 alert(data.length) 外,所有警报都返回正确的值;它返回 undefined 并且绘图 div 出现,其中写有标签 没有数据