关键代码：

        /// <summary>        /// 创建基准线ConstantLine        /// </summary>        /// <param name="chart">ChartControl</param>        /// <param name="ctAxisValue">基准线数值</param>        /// <param name="ctLegendText">基准线图例文字</param>        /// <param name="ctTitle">基准线文字</param>        /// <param name="ctTitleColor">基准线字体颜色</param>        /// <param name="ctLineColor">基准线颜色</param>        /// <param name="ctLineStyle">基准线样式</param>        public static void CreateConstantLine(this ChartControl chart, int ctAxisValue, string ctLegendText, string ctTitle, Color ctTitleColor, Color ctLineColor, DashStyle ctLineStyle)        {            XYDiagram _diagram = (XYDiagram)chart.Diagram;            if (_diagram != null)            {                ConstantLine _ctLine = new ConstantLine();                _ctLine.AxisValue = http://www.mamicode.com/ctAxisValue;"kwrd">true;                _ctLine.ShowInLegend = true;                _ctLine.LegendText = ctLegendText;                _ctLine.ShowBehind = false;                _ctLine.Title.Visible = true;                _ctLine.Title.Text = ctTitle;                _ctLine.Title.TextColor = ctTitleColor;                _ctLine.Title.Antialiasing = false;                _ctLine.Title.Font = new Font("Tahoma", 14, FontStyle.Bold);                _ctLine.Title.ShowBelowLine = true;                _ctLine.Title.Alignment = ConstantLineTitleAlignment.Far;                _ctLine.Color = ctLineColor;                _ctLine.LineStyle.DashStyle = ctLineStyle;                _ctLine.LineStyle.Thickness = 2;                _diagram.AxisY.ConstantLines.Add(_ctLine);            }        }

<style type="text/css">.csharpcode, .csharpcode pre{ font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/}.csharpcode pre { margin: 0em; }.csharpcode .rem { color: #008000; }.csharpcode .kwrd { color: #0000ff; }.csharpcode .str { color: #006080; }.csharpcode .op { color: #0000c0; }.csharpcode .preproc { color: #cc6633; }.csharpcode .asp { background-color: #ffff00; }.csharpcode .html { color: #800000; }.csharpcode .attr { color: #ff0000; }.csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em;}.csharpcode .lnum { color: #606060; }</style>代码使用：

chartControl1.CreateConstantLine(25, "理论利润", "理论利润", Color.Red, Color.Red, DashStyle.Dash);

运行效果：

希望有所帮助！谢谢！

[DevExpress]ChartControl之基准线示例