asp.net mvc 4 - c#中十进制[]到双进位[]的转换

我正在使用以下代码在asp.net-mvc4应用程序中制作绘图

System.Web.UI.DataVisualization.Charting.Chart chart = new System.Web.UI.DataVisualization.Charting.Chart();
        chart.BackColor = Color.Transparent;
        chart.Width = Unit.Pixel(700);
        chart.Height = Unit.Pixel(420);
        chart.BackColor = Color.FromArgb(211, 223, 240);
        chart.BorderlineDashStyle = ChartDashStyle.Solid;
        chart.BackSecondaryColor = Color.White;
        chart.BackGradientStyle = GradientStyle.TopBottom;
        chart.BorderlineWidth = 1;
        chart.Palette = ChartColorPalette.BrightPastel;
        chart.BorderlineColor = Color.FromArgb(26, 59, 105);
        chart.RenderType = RenderType.BinaryStreaming;
        chart.BorderSkin.SkinStyle = BorderSkinStyle.Emboss;
        chart.AntiAliasing = AntiAliasingStyles.All;
        chart.TextAntiAliasingQuality = TextAntiAliasingQuality.Normal;
        Series series1 = new Series("Series1");
        series1.ChartArea = "ca1";
        series1.ChartType = SeriesChartType.Line;
        series1.Font = new Font("Verdana", 8.25f, FontStyle.Regular);
        series1.Points.Add(new DataPoint
        {
            AxisLabel = "Value1",
            YValues = new double[] { 100 }
        });
        series1.Points.Add(new DataPoint
        {
            AxisLabel = "Value2",
            YValues = new double[] { 500 }
        });
        chart.Series.Add(series1);
        ChartArea ca1 = new ChartArea("ca1");
        ca1.BackColor = Color.Transparent;
        chart.ChartAreas.Add(ca1);
        using (var ms = new MemoryStream())
        {
            chart.SaveImage(ms, ChartImageFormat.Png);
            ms.Seek(0, SeekOrigin.Begin);
            return File(ms.ToArray(), "image/png", "mychart.png");
        }

现在我有我的数据点作为一个数组从数据库保存在returnValue。我添加了如下编辑过的数据点

series1.Points.Add(new DataPoint
        {
            AxisLabel = "Value1",
            YValues = new double[] {returnValue.yData}
        });

错误是

Conversion from decimal[] to double is not possible

series1.Points.Add(new DataPoint
{
    AxisLabel = "Value1",
    YValues = returnValue.yData.Select(Convert.ToDouble).ToArray()
});