public ColorPickerItemCollection Items {get;}

private void CreateGcColorPickerLookLikeWordPadColorPickerWithItems()
{
    // Create an instance of GcColorPicker control.
    GcColorPicker gcColorPicker1 = new GcColorPicker();

    // Initialize the Name and Location of the gcColorPicker.
    gcColorPicker1.Name = "gcColorPicker";
    gcColorPicker1.Location = new Point(10, 50);

    // Use CustomColorsPalatte to create a color picker which look like 
    // the color picker in WordPad.
    gcColorPicker1.Items.Clear();
    gcColorPicker1.Items.Add(new CustomColorsPalette());

    // adds gcColorPicker to the form.
    this.Controls.Add(gcColorPicker1);

    // Create an instance of GcColorPicker control.
    GcColorPicker gcColorPicker2 = new GcColorPicker();

    // Initialize the Name and Location of the gcColorPicker.
    gcColorPicker2.Name = "gcColorPicker";
    gcColorPicker2.Location = new Point(10, 90);

    // Use CustomColorsPalatte to create a color picker which look like 
    // the color picker in WordPad.
    gcColorPicker2.Items.Clear();
    CustomColorsPalette s = new CustomColorsPalette();
    s.CaptionVisible = false;
    s.ColorBlockSize = 14;
    s.ColumnSpace = 6;
    s.RowSpace = 0;
    s.ColumnCount = 5;
    s.Colors = new Color[30];
    s.Colors[0] = Color.White;
    s.Colors[1] = Color.Red;
    s.Colors[2] = Color.FromArgb(192, 80, 77);
    s.Colors[3] = Color.FromArgb(209, 99, 73);
    s.Colors[4] = Color.FromArgb(221, 132, 132);
    s.Colors[5] = Color.FromArgb(204, 204, 204);
    s.Colors[6] = Color.FromArgb(255, 192, 0);
    s.Colors[7] = Color.FromArgb(247, 150, 70);
    s.Colors[8] = Color.FromArgb(209, 144, 73);
    s.Colors[9] = Color.FromArgb(243, 164, 71);
    s.Colors[10] = Color.FromArgb(165, 165, 165);
    s.Colors[11] = Color.Yellow;
    s.Colors[12] = Color.FromArgb(155, 187, 89);
    s.Colors[13] = Color.FromArgb(204, 180, 0);
    s.Colors[14] = Color.FromArgb(223, 206, 4);
    s.Colors[15] = Color.FromArgb(102, 102, 102);
    s.Colors[16] = Color.FromArgb(0, 176, 80);
    s.Colors[17] = Color.FromArgb(75, 172, 198);
    s.Colors[18] = Color.FromArgb(143, 176, 140);
    s.Colors[19] = Color.FromArgb(165, 181, 146);
    s.Colors[20] = Color.FromArgb(51, 51, 51);
    s.Colors[21] = Color.FromArgb(0, 77, 187);
    s.Colors[22] = Color.FromArgb(79, 129, 189);
    s.Colors[23] = Color.FromArgb(100, 107, 134);
    s.Colors[24] = Color.FromArgb(128, 158, 194);
    s.Colors[25] = Color.Black;
    s.Colors[26] = Color.FromArgb(155, 0, 211);
    s.Colors[27] = Color.FromArgb(128, 100, 162);
    s.Colors[28] = Color.FromArgb(158, 124, 124);
    s.Colors[29] = Color.FromArgb(156, 133, 192);
    gcColorPicker2.Items.Add(new SeparateLineItem());
    AutomaticColorItem a = new AutomaticColorItem();
    gcColorPicker2.Items.Add(a);
    gcColorPicker2.Items.Add(s);
    gcColorPicker2.Items.Add(new SeparateLineItem());
    gcColorPicker2.Items.Add(new MoreColorsItem());
    gcColorPicker2.Items.Add(new SeparateLineItem());

    // adds gcColorPicker to the form.
    this.Controls.Add(gcColorPicker2);
}

private void CreateGcColorPickerLookLikeVisualStudioColorPickerWithItems()
{
    // Create an instance of GcColorPicker control.
    GcColorPicker gcColorPicker = new GcColorPicker();

    // Initialize the Name and Location of the gcColorPicker.
    gcColorPicker.Name = "gcColorPicker";
    gcColorPicker.Location = new Point(10, 50);

    // Use CustomColorsPalatte to create a color picker which look like 
    // the color picker in VisualStudio.
    gcColorPicker.Items.Clear();
    gcColorPicker.Items.Add(new VisualStudioColorEditor());

    // adds gcColorPicker to the form.
    this.Controls.Add(gcColorPicker);
}

private void CreateGcColorPickerHasBiggerColorBlockSizeWithItems()
{
    // Create an instance of GcColorPicker control.
    GcColorPicker gcColorPicker = new GcColorPicker();

    // Initialize the Name and Location of the gcColorPicker.
    gcColorPicker.Name = "gcColorPicker";
    gcColorPicker.Location = new Point(10, 50);

    // Use CustomColorsPalatte to create a color picker which 
    // has bigger color block size.
    gcColorPicker.Items.Clear();
    ThemeColorsPalette themeColorsPalette = new ThemeColorsPalette();
    themeColorsPalette.CaptionFont = new Font("Segoe UI Semibold", 13F, FontStyle.Bold | FontStyle.Italic);
    themeColorsPalette.ColorBlockSize = 20;
    gcColorPicker.Items.Add(themeColorsPalette);

    // adds gcColorPicker to the form.
    this.Controls.Add(gcColorPicker);
}