BinaryColorPickerDropDown

What it is for

Use it directly when a colour should be picked from a button, a toolbar or a grid cell rather than a combo box. Call Show() with a point in screen coordinates and handle BinaryColorPickerSelectedColorChanged.

The three tabs

• Custom – an 8 x 8 palette of cells 20 logical pixels square: six shades of each of eight hues, over two rows of white cells. Right-clicking a cell in the two bottom rows opens a colour dialog; the colour chosen there replaces the cell's colour and is selected, and the window stays open. A left click selects a cell's colour and closes the window.
• Web – the named web colours, from Transparent and Black to YellowGreen.
• System – the Windows system colours, such as Control and WindowText.

The window opens on the tab holding SelectedColor: the System or Web tab for a named colour, the Custom tab for any other. It closes when a colour is chosen, when the user clicks anywhere outside it, or when it loses activation.

The window has no border of its own beyond a one-pixel black line, does not appear in the task bar, and sizes itself for the display it opens on.

using System;
using System.Drawing;
using System.Windows.Forms;
using Binarymission.WinForms.Controls.ColorPickers;

public class CategoryEditor : UserControl
{
    private readonly Button colourButton = new Button { Text = "Category colour", Width = 140 };
    private readonly BinaryColorPickerDropDown colourWindow = new BinaryColorPickerDropDown();

    public CategoryEditor()
    {
        Controls.Add(colourButton);

        colourWindow.BinaryColorPickerSelectedColorChanged += (sender, e) =>
            colourButton.BackColor = colourWindow.SelectedColor;

        colourButton.Click += (sender, e) =>
        {
            colourWindow.SelectedColor = colourButton.BackColor;
            // Open just below the button, in screen coordinates.
            colourWindow.Show(colourButton.PointToScreen(new Point(0, colourButton.Height)));
        };
    }

    protected override void Dispose(bool disposing)
    {
        if (disposing)
        {
            colourWindow.Dispose();
        }

        base.Dispose(disposing);
    }
}