Question

我想计算一个月内新用户的数量。然而，这是我收到的输出。我如何将重复的几个月分组到＆＃34; Jan＆＃34;，＆＃34; Nov＆＃34;。非常感谢你的帮助。

public ActionResult UserPerMonth()
{

    var _con = new DBEntities();
    ArrayList xValue = new ArrayList();
    ArrayList yValue = new ArrayList();
    var results = (from c in _con.Users select c);
    results.ToList().ForEach(rs => yValue.Add(rs.id.ToString().Count()));
    results.ToList().ForEach(rs => xValue.Add(rs.date.Value.ToString("MMM-yyyy")));

    var chart = new Chart(width: 300, height: 200)
                .AddTitle("Users per month")
                .AddLegend()
                .AddSeries(
                chartType: "Column",
                xValue: xValue,
                yValues: yValue)
                .GetBytes("png");
     return File(chart, "image/png");
 }

Answer 1

可能有更简洁的方法，但这对我有用。为图表数据添加一个类，例如

public class ChartData
{
    public string Month { get; set; }
    public int Count { get; set; }
}

然后你可以使用带有groupby和count的linq查询来获取数据并将其放入ChartData类型，然后将这些值移动到相关的轴：

public ActionResult UserPerMonth()
{

    var _con = new DBEntities();
    ArrayList xValue = new ArrayList();
    ArrayList yValue = new ArrayList();

    var results = (from c in _con.Users select c);

    var axis = results.GroupBy(r => r.date.Value.ToString("MMM-yyyy"))
            .Select(r => new ChartData
            {
                Month = r.Key,
                Count = r.Count()
            }).ToList();

    foreach (var item in axis)
    {
        xValue.Add(item.Month);
        yValue.Add(item.Count);
    }


    var chart = new Chart(width: 300, height: 200)
        .AddTitle("Users per month")
        .AddLegend()
        .AddSeries(
            chartType: "Column",
            xValue: xValue,
            yValues: yValue)
        .GetBytes("png");
    return File(chart, "image/png");
}

按月分组MVC图表

1 个答案: