MasterDetailGridViewComboBox.csx

#r "System.Windows.Forms"
#r "System.Drawing"

using System.Windows.Forms;
using System.Drawing;
using System;

Application.Run(new Form1());

public class Form1 : Form
{
    public Form1()
    {
        this.Load += FormLoad;
        this.Controls.Add(dataGridView1);
    }

    private void FormLoad(object sender, EventArgs e)
    {
        AddColorColumn();
    }

    private DataGridView dataGridView1 = new DataGridView();
    DataGridViewComboBoxColumn comboBoxColumn;
    DataGridViewComboBoxColumn comboBoxDetailColumn;

    private void AddColorColumn()
    {
        comboBoxColumn = new DataGridViewComboBoxColumn();
        comboBoxColumn.Items.AddRange(
            Color.Red, Color.Yellow, Color.Green, Color.Blue);
        comboBoxColumn.ValueType = typeof(Color);
        dataGridView1.Columns.Add(comboBoxColumn);
        comboBoxDetailColumn = new DataGridViewComboBoxColumn();
        comboBoxDetailColumn.ValueType = typeof(Color);
        dataGridView1.Columns.Add(comboBoxDetailColumn);
        dataGridView1.CellEndEdit += dataGridView1_CellEndEdit;
    }

    private void dataGridView1_CellEndEdit(object sender, DataGridViewCellEventArgs e)
    {
        DataGridView dataGridView = sender as DataGridView;
        DataGridViewComboBoxCell masterCell =
            (DataGridViewComboBoxCell)dataGridView.Rows[e.RowIndex].Cells[0];
        DataGridViewComboBoxCell detailCell =
            (DataGridViewComboBoxCell)dataGridView.Rows[e.RowIndex].Cells[1];

        if (masterCell.Value != null && e.ColumnIndex == 0)
        {
            detailCell.Items.Clear();

            Color color = (Color)masterCell.Value;
            var oldValue = detailCell.Value;
            detailCell.Value = null;

            switch (color.Name)
            {
                case "Red":
                    detailCell.Items.AddRange(
                    Color.DarkRed, Color.IndianRed, Color.MediumVioletRed, Color.PaleVioletRed);
                    break;
                case "Green":
                    detailCell.Items.AddRange(
                    Color.Green, Color.DarkGreen, Color.LightSeaGreen, Color.LawnGreen);
                    break;
                case "Blue":
                    detailCell.Items.AddRange(
                    Color.CornflowerBlue, Color.LightBlue, Color.LightSteelBlue, Color.PowderBlue);
                    break;
                case "Yellow":
                    detailCell.Items.AddRange(
                    Color.GreenYellow, Color.LightYellow, Color.YellowGreen, Color.LightGoldenrodYellow);
                    break;
            }

            if (oldValue != null && detailCell.Items.Contains(oldValue))
            {
                detailCell.Value = oldValue;
            }
        }
    }
}