散布図（シンボルのみの折れ線グラフも含む）やローソク足グラフで、指定した特定のデータポイントの色を変更するには、シリーズのSymbolRenderingイベントを使用し、Engine.SetFillメソッド、SetStrokeメソッドを実行します。



◎サンプルコード（VB）

Imports C1.Chart
Imports C1.Win.Chart

Public Class Form1
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        ' データテーブルの設定
        Dim dt1 As DataTable = New DataTable()

        dt1.Columns.AddRange(New DataColumn() {
            New DataColumn("ID", GetType(Integer)), New DataColumn("個数", GetType(Integer))})
        dt1.Rows.Add(1, 10)
        dt1.Rows.Add(2, 50)
        dt1.Rows.Add(3, 60)
        dt1.Rows.Add(4, 30)
        dt1.Rows.Add(5, 20)

        ' （１）散布図
        ' チャートタイプの設定
        FlexChart1.ChartType = ChartType.Scatter
        FlexChart1.DataSource = dt1
        ' FlexChartへのバインド
        FlexChart1.BindingX = "ID"
        FlexChart1.Binding = "個数"
        FlexChart1.Header.Content = "散布図"
        FlexChart1.Series(0).Name = ""

        '（２）折れ線グラフ（シンボルのみ）
        ' チャートタイプの設定
        FlexChart2.ChartType = ChartType.LineSymbols
        FlexChart2.Series(0).Style.Fill = Brushes.Blue
        FlexChart2.Series(0).Style.Stroke = Brushes.Transparent
        ' FlexChartへのバインド
        FlexChart2.DataSource = dt1
        FlexChart2.BindingX = "ID"
        FlexChart2.Binding = "個数"
        FlexChart2.Header.Content = "折れ線グラフ（シンボルのみ）"
        FlexChart2.Series(0).Name = ""

        ' （３）ローソク足
        'データテーブルの設定
        Dim dt2 As DataTable = New DataTable()
        dt2.Columns.AddRange(New DataColumn() {
            New DataColumn("X", GetType(Integer)),
            New DataColumn("Y-High", GetType(Integer)),
            New DataColumn("Y-Low", GetType(Integer)),
            New DataColumn("Y-Open", GetType(Integer)),
            New DataColumn("Y-Close", GetType(Integer))
        })
        dt2.Rows.Add(1, 120, 95, 110, 110)
        dt2.Rows.Add(2, 135, 105, 115, 115)
        dt2.Rows.Add(3, 140, 110, 120, 120)
        dt2.Rows.Add(4, 110, 90, 100, 100)
        dt2.Rows.Add(5, 130, 90, 105, 105)
        ' チャートタイプの設定
        FlexChart3.ChartType = ChartType.Candlestick
        ' FlexChartへのバインド
        FlexChart3.DataSource = dt2
        FlexChart3.BindingX = "X"
        FlexChart3.Binding = "Y-High,Y-Low,Y-Open,Y-Close"
        FlexChart3.Header.Content = "ローソク足"
        FlexChart3.Series(0).Name = ""

        ' SymbolRenderingイベントの追加
        Dim series1 As Series = FlexChart1.Series(0)
        AddHandler series1.SymbolRendering, AddressOf series1_SymbolRendering

        Dim series2 As Series = FlexChart2.Series(0)
        AddHandler series2.SymbolRendering, AddressOf series2_SymbolRendering

        Dim series3 As Series = FlexChart3.Series(0)
        AddHandler series3.SymbolRendering, AddressOf series3_SymbolRendering

    End Sub

    Private Sub series1_SymbolRendering(ByVal sender As Object, ByVal e As RenderSymbolEventArgs)
        If e.Index = 2 Then
            e.Engine.SetFill(Brushes.Red)
            e.Engine.SetStroke(Brushes.Yellow)
        End If
    End Sub

    Private Sub series2_SymbolRendering(ByVal sender As Object, ByVal e As RenderSymbolEventArgs)
        If e.Index = 2 Then
            e.Engine.SetFill(Brushes.Red)
            e.Engine.SetStroke(Brushes.Yellow)
        End If
    End Sub

    Private Sub series3_SymbolRendering(ByVal sender As Object, ByVal e As RenderSymbolEventArgs)
        If e.Index = 2 Then
            e.Engine.SetStroke(Brushes.DarkRed)
        End If
    End Sub
End Class

◎サンプルコード（C#）

using C1.Chart;
using C1.Win.Chart;

namespace prj_C1FlexChart
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();

            //データテーブルの設定
            DataTable dt1 = new DataTable();
            dt1.Columns.AddRange(new DataColumn[]{
                new DataColumn("ID", typeof(Int32)),new DataColumn("個数", typeof(Int32))});
            dt1.Rows.Add(1, 10);
            dt1.Rows.Add(2, 50);
            dt1.Rows.Add(3, 60);
            dt1.Rows.Add(4, 30);
            dt1.Rows.Add(5, 20);

            //（１）散布図
            // チャートタイプの設定
            flexChart1.ChartType = ChartType.Scatter;
            // FlexChartへのバインド
            flexChart1.DataSource = dt1;
            flexChart1.BindingX = "ID";
            flexChart1.Binding = "個数";
            flexChart1.Header.Content = "散布図";
            flexChart1.Series[0].Name = "";

            //（２）折れ線グラフ（シンボルのみ）
            // チャートタイプの設定
            flexChart2.ChartType = ChartType.LineSymbols;
            flexChart2.Series[0].Style.Fill = Brushes.Blue;
            flexChart2.Series[0].Style.Stroke = Brushes.Transparent;
            // FlexChartへのバインド
            flexChart2.DataSource = dt1;
            flexChart2.BindingX = "ID";
            flexChart2.Binding = "個数";
            flexChart2.Header.Content = "折れ線グラフ（シンボルのみ）";
            flexChart2.Series[0].Name = "";

            // （３）ローソク足
            //データテーブルの設定
            DataTable dt2 = new DataTable();
            dt2.Columns.AddRange(new DataColumn[]
            {
                new DataColumn("X", typeof(Int32)),
                new DataColumn("Y-High", typeof(double)),
                new DataColumn("Y-Low", typeof(double)),
                new DataColumn("Y-Open", typeof(double)),
                new DataColumn("Y-Close", typeof(double))
            });
            dt2.Rows.Add(1, 120, 95, 110, 110);
            dt2.Rows.Add(2, 135, 105, 115, 115);
            dt2.Rows.Add(3, 140, 110, 120, 120);
            dt2.Rows.Add(4, 110, 90, 100, 100);
            dt2.Rows.Add(5, 130, 90, 105, 105);

            // チャートタイプの設定
            flexChart3.ChartType = ChartType.Candlestick;
            // FlexChartへのバインド
            flexChart3.DataSource = dt2;
            flexChart3.BindingX = "X";
            flexChart3.Binding = "Y-High,Y-Low,Y-Open,Y-Close";
            flexChart3.Header.Content = "ローソク足";
            flexChart3.Series[0].Name = "";
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            // SymbolRenderingイベントの追加
            Series series1 = flexChart1.Series[0];
            series1.SymbolRendering += series1_SymbolRendering;

            Series series2 = flexChart2.Series[0];
            series2.SymbolRendering += series2_SymbolRendering;

            Series series3 = flexChart3.Series[0];
            series3.SymbolRendering += series3_SymbolRendering;
        }

        private void series1_SymbolRendering(object sender, RenderSymbolEventArgs e)
        {
            if (e.Index == 2)
            {
                e.Engine.SetFill(Brushes.Red);
                e.Engine.SetStroke(Brushes.Yellow);
            }
        }

        private void series2_SymbolRendering(object sender, RenderSymbolEventArgs e)
        {
            if (e.Index == 2)
            {
                e.Engine.SetFill(Brushes.Red);
                e.Engine.SetStroke(Brushes.Yellow);
            }
        }

        private void series3_SymbolRendering(object sender, RenderSymbolEventArgs e)
        {
            if (e.Index == 2)
            {
                e.Engine.SetStroke(Brushes.DarkRed);
            }
        }
    }
}