是否可以从通用列表中设置图表数据源？

Question

I have a list created from a linq query that contains 2 columns of data.

var result = root.Descendants().Elements("sensor")
                 .Where(el => (string)el.Attribute("name") == "Sensor1") 
                 .Elements("evt") 
                 .Select(el => new { t1 = el.Attribute("time").Value, 
                                     v1 = el.Attribute("val").Value }) 
                 .ToList()

I'm trying to use the chart control datasource to use that list, but when I call the bind method I receive this error:

System.ArgumentException was unhandled HResult=-2147024809
Message=Series data points do not support values of type <>f__AnonymousType0`2[System.Double,System.Decimal] only values of these types can be used: Double, Decimal, Single, int, long, uint, ulong, String, DateTime, short, ushort.

//result is a generic list defined as var result = root.Descendants()
chart1.DataSource = result;
chart1.DataBind(); // This is line that causes the exception.

Regards.

Answer 1

Yes it is possible, but not by binding the list to the Chart itself.

There are several quite different methods to do Chart Databinding , all with different sets of pros and cons..

I suggest using the Series.Points.DataBindXY or Series.Points.DataBind methods.

Here is an example:

// create a list with test data:
List<PointF> points = new List<PointF>();
for (int i = 0; i < 100; i++) points.Add(new PointF(i, 1f * i / 2f * R.Next(8)));

Now create a generic list from it:

var al = points.Select(x => new { t1 = x.X, v1 = x.Y }).ToList();

Now this works:

someSeries.Points.DataBindXY(al, "t1", al, "v1");

or also this:

someSeries.DataBind(al, "t1", "v1", "" );

In your case you would write maybe this:

chart1.Series[0].Points.DataBind(result, "t1", "v1");

Note that a Chart typically can only display pairs of values whereas a DGV can create as many columns as the DataSource has. So Chart needs a little help in finding the x- and y-values..