wpf日历控件制作过程分析(2)---自定义样式属性

接上篇wpf日历控件制作过程分析(1)---定义header

在header中,我们看到了定义一个自定义样式TitleStyle

1.自定义样式

看后台代码定义

Code
        /**//// <summary>
        /// The DependencyProperty for the TitleStyle property.
        /// Flags:              none
        /// Default Value:      null
        /// </summary>
        public static readonly DependencyProperty TitleStyleProperty =
                DependencyProperty.Register(
                        "TitleStyle",
                        typeof(Style),
                        typeof(MonthCalendar),
                        new FrameworkPropertyMetadata(
                                (Style)null));

        /**//// <summary>
        /// TitleStyle property
        /// </summary>
        public Style TitleStyle
        {
            get { return (Style)GetValue(TitleStyleProperty); }
            set { SetValue(TitleStyleProperty, value); }
        }

应该说,是比较简单的,默认样式为null,如果指定了样式的话,则会覆盖默认的样式

2.不重叠选择样式

为日历的前进和后退按钮定义两个样式

Code
        /**//// <summary>
        /// The DependencyProperty for the PreviousButtonStyle property.
        /// Flags:              none
        /// Default Value:      null
        /// </summary>
        public static readonly DependencyProperty PreviousButtonStyleProperty =
                DependencyProperty.Register(
                        "PreviousButtonStyle",
                        typeof(Style),
                        typeof(MonthCalendar),
                        new FrameworkPropertyMetadata(
                                (Style)null, new PropertyChangedCallback(OnPreviousButtonStyleChanged)));

        /**//// <summary>
        /// PreviousButtonStyle property
        /// </summary>
        public Style PreviousButtonStyle
        {
            get { return (Style)GetValue(PreviousButtonStyleProperty); }
            set { SetValue(PreviousButtonStyleProperty, value); }
        }

        private static void OnPreviousButtonStyleChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            ((MonthCalendar)d).RefreshPreviousButtonStyle();
        }

        /**//// <summary>
        /// The DependencyProperty for the NextButtonStyle property.
        /// Flags:              none
        /// Default Value:      null
        /// </summary>
        public static readonly DependencyProperty NextButtonStyleProperty =
                DependencyProperty.Register(
                        "NextButtonStyle",
                        typeof(Style),
                        typeof(MonthCalendar),
                        new FrameworkPropertyMetadata(
                                (Style)null, new PropertyChangedCallback(OnNextButtonStyleChanged)));

        /**//// <summary>
        /// NextButtonStyle property
        /// </summary>
        public Style NextButtonStyle
        {
            get { return (Style)GetValue(NextButtonStyleProperty); }
            set { SetValue(NextButtonStyleProperty, value); }
        }

        private static void OnNextButtonStyleChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            ((MonthCalendar)d).RefreshNextButtonStyle();
        }

再来这个RefreshNextButtonStyle方法

Code
        private void RefreshNextButtonStyle()
        {
            ButtonBase nextButton = GetTemplateChild(c_NextButtonName) as ButtonBase;
            if (nextButton != null)
            {
                if (NextButtonStyle == null)
                {
                    if (_defaultNextButtonStyle == null)
                    {
                        _defaultNextButtonStyle = FindResource(new ComponentResourceKey(typeof(MonthCalendar), "NextButtonStyleKey")) as Style;
                    }
                    nextButton.Style = _defaultNextButtonStyle;
                }
                else
                {
                    nextButton.Style = NextButtonStyle;
                }
            }
        }

注意点:
1.GetTemplateChild可以获取到xaml中声明了key值的元素,c_NextButtonName变量就是xaml定义的key,此key应该公开给控件的使用者,可调整样式
2.用TemplatePart公开模块样式,如两个按钮的key值

    [TemplatePart(Name = "PART_PreviousButton", Type = typeof(ButtonBase))]
    [TemplatePart(Name = "PART_NextButton", Type = typeof(ButtonBase))]

3._defaultNextButtonStyle还是从xaml去找,其目的是为了自定义样式不会与默认样式发生冲突.可以title样式比较
4.构建可视化模板需要在OnApplyTemplate方法中使用,如上面的RefreshNextButtonStyle方法必须在OnApplyTemplate方法中调用