在上一章讲了单选框样式，单选扩展依赖属性类继承于RadioButton。然后在自定义样式，RadioButton中需要把GroupName设置为同一组名称即可。

复选框实现原理同单选框相同，主要区别在于实现多选需要继承ToggleButton类，此类每个按钮是可以单独选择的。

先看一下实现效果：

增加几项依赖属性和单选框一样。这里就不再多介绍。

/// <summary>
    /// 多选框
    /// </summary>
    public class NbCheckBox : NbToggleButton
    {
        #region ctor

        static NbCheckBox()
        {
            DefaultStyleKeyProperty.OverrideMetadata(typeof(NbCheckBox), new FrameworkPropertyMetadata(typeof(NbCheckBox)));
        }

        /// <summary>
        ///
        /// </summary>
        public NbCheckBox()
        {
            IsHitTestVisibleInChrome = true;
        }

        #endregion ctor

        public Brush OptionMarkBackground
        {
            get { return (Brush)GetValue(OptionMarkBackgroundProperty); }
            set { SetValue(OptionMarkBackgroundProperty, value); }
        }

        // Using a DependencyProperty as the backing store for OptionMarkBackground.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty OptionMarkBackgroundProperty =
            DependencyProperty.Register("OptionMarkBackground", typeof(Brush), typeof(NbCheckBox), new PropertyMetadata(Brushes.Transparent));

        public bool ShowOptionMark
        {
            get { return (bool)GetValue(ShowOptionMarkProperty); }
            set { SetValue(ShowOptionMarkProperty, value); }
        }

        // Using a DependencyProperty as the backing store for ShowOptionMark.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty ShowOptionMarkProperty =
            DependencyProperty.Register("ShowOptionMark", typeof(bool), typeof(NbCheckBox), new PropertyMetadata(true));

        public double OptionMarkHeight
        {
            get { return (double)GetValue(OptionMarkHeightProperty); }
            set { SetValue(OptionMarkHeightProperty, value); }
        }

        // Using a DependencyProperty as the backing store for ShowOptionMarkHeight.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty OptionMarkHeightProperty =
            DependencyProperty.Register("OptionMarkHeight", typeof(double), typeof(NbCheckBox), new PropertyMetadata(16d));

        public double OptionMarkWidth
        {
            get { return (double)GetValue(OptionMarkWidthProperty); }
            set { SetValue(OptionMarkWidthProperty, value); }
        }

        // Using a DependencyProperty as the backing store for ShowOptionMarkWidth.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty OptionMarkWidthProperty =
            DependencyProperty.Register("OptionMarkWidth", typeof(double), typeof(NbCheckBox), new PropertyMetadata(16d));
    }

复选框样式代码如下：

复选功能就实现了，接下来就是调用代码示例：