Color Selector is a small application developed in Visual C# which displays all named color along with a small strip of the color. Upon selecting the color the below panel will be updated with the selected color. As shown in the 2 images.

The DrawItem event of the combo box control has to be implemented in the code and DrawMode property for the combo box control must be set to OwnerDrawFixed in design time in order to let the DrawItem event work.

Design & Coding Application:

Create a Visual C# Windows Forms project in either Visual Studio 2005 / 2008 with Single Form which contains a button (btnLoadColorList), combo box(cmbColorList) and panel (pnlColorTester). Set the DrawMode property of cmbColorList to OwnerDrawFixed and DropDown height property of cmbColorList to 80.

Code for the Form will be as follows.

using System;
using System.Collections;
using System.Reflection;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace ColorSelector
{
    public partial class frmColorTester : Form
    {
        public frmColorTester()
        {
            InitializeComponent();
        }

        private void btnLoadColorList_Click(object sender, EventArgs e)
        {
            try
            {
                ArrayList ColorList = new ArrayList();
                Type colorType = typeof(System.Drawing.Color);
                PropertyInfo[] propInfoList =
                    colorType.GetProperties(BindingFlags.Static | BindingFlags.DeclaredOnly |
                    BindingFlags.Public);
                foreach (PropertyInfo propInfo in propInfoList)
                { this.cmbColorList.Items.Add(propInfo.Name); }
            }
            catch (Exception ex)
            { MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); }
        }

        private void cmbColorList_DrawItem(object sender, DrawItemEventArgs e)
        {
            try
            {
                Graphics objGraphics = e.Graphics;
                Rectangle objRectange = e.Bounds;
                if (e.Index >= 0)
                {
                    string strColorName = ((ComboBox)sender).Items[e.Index].ToString();
                    Font objFont = new Font("Arial", 9, FontStyle.Regular);
                    Color objColor = Color.FromName(strColorName);
                    Brush objBrush = new SolidBrush(objColor);
                    objGraphics.DrawString(strColorName, objFont, Brushes.Black,
                        objRectange.X, objRectange.Top);
                    objGraphics.FillRectangle(objBrush, objRectange.X + 125,
                        objRectange.Y + 5, objRectange.Width - 10, objRectange.Height - 10);
                }
            }
            catch (Exception ex)
            { MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); }
        }

        private void cmbColorList_SelectedIndexChanged(object sender, EventArgs e)
        {
            try
            {
                string strColorSelected = cmbColorList.Items[cmbColorList.SelectedIndex].ToString();
                pnlColorTester.BackColor = Color.FromName(strColorSelected);
            }
            catch (Exception ex)
            { MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error); }
        }
    }
}

You can download the sample application developed in Visual Studio 2008 from here.