.net web图表类

用法：

Response.ContentType = "image/png";
            string[] xValues, yValues;
            LineChart line = new LineChart(Color.White);
            line.VerticalLabel = "告警数量";
            line.ShowLegend = false;
            line.ShowData = true;
            line.Height = 250;
            line.Width = 250;
            GetValues(out xValues, out yValues); //填充数据
            line.CollectDataPoints(xValues, yValues);
            Bitmap StockBitMap = line.Draw();
            MemoryStream memStream = new MemoryStream();
            StockBitMap.Save(memStream, ImageFormat.Png);
            memStream.WriteTo(Response.OutputStream);