Winforms control for binary representation of an integer

Question

I'm perhaps not articulating this correctly (and apologies if this is the case), but is anyone aware of a Winforms control that could be used to both represent an integer in binary form, and allow the user to 'switch' every separate bit?

I've clobbered together a rough approach for this - using a CheckListBox control, and a couple of enum lists, adding a checkbox for each bit at design time.

This works, but it's not a neat solution, and I wondered perhaps if there was a neater approach. I may need to repeat the work in other projects, so thought about knocking up a custom control to do this, but if anyone is aware of an existing way to do this, I'd be interested!

Answer 1

I would try this approach:

Make bitwise enum:

[Flags]
public enum MyBits
{
    MyFirstBit = 1 << 0,
    MySecondBit = 1 << 1,
    MyThirdBit = 1 << 2,
};

Now create a custom control based on CheckedListBox which accepts any enum as input. Ue this enum to fill your control with checkboxes. One checkbox per enum:

public partial class EnumEditor : CheckedListBox
{
    public EnumEditor()
    {
        InitializeComponent();
        ItemCheck += EnumEditor_ItemCheck;
    }

    private object _value;
    public object Value
    {
        get
        {
            return _value;
        }
        set
        {
            if (value == null)
                throw new ArgumentNullException("Value");
            if (!value.GetType().IsEnum)
                throw new ArgumentNullException("Value should be enumerable.");
            if (value.GetType().GetCustomAttributes(typeof(FlagsAttribute), false).Length == 0)
                throw new ArgumentNullException("Value must be marked with [Flags].");
            _value = value;
            Rebuild();
        }
    }

    public event EventHandler<EnumValueChangeEventArgs> ValueChanged;

    protected virtual void OnValueChanged(object value)
    {
        EventHandler<EnumValueChangeEventArgs> valueChanged = ValueChanged;
        if (valueChanged != null)
            valueChanged(this, new EnumValueChangeEventArgs { Value = value });
    }

    private void Rebuild()
    {
        Items.Clear();
        if (_value != null)
        {
            foreach (object value in Enum.GetValues(_value.GetType()))
                Items.Add(value, ((int)_value & (int)value) != 0);
        }
    }

    void EnumEditor_ItemCheck(object sender, ItemCheckEventArgs e)
    {
        ulong bits = Convert.ToUInt64(_value);
        ulong bit = Convert.ToUInt64(Items[e.Index]);
        if (e.NewValue == CheckState.Checked)
            bits = bits | bit;
        else
            bits = bits & ~bit;
        _value = Enum.ToObject(_value.GetType(), bits);
        OnValueChanged(_value);
    }
}

public class EnumValueChangeEventArgs : EventArgs
{
    public object Value
    {
        get;
        set;
    }
}