WPF编程宝典P18----ColorPicker 和FlipPanel的讲解

一,ColorPicker的实现

1,自定义属性

  #region ColorPick Of the Book
    [TemplatePart(Name = "PART_RedSlider", Type = typeof(RangeBase))]
    [TemplatePart(Name = "PART_BlueSlider", Type = typeof(RangeBase))]
    [TemplatePart(Name = "PART_GreenSlider", Type = typeof(RangeBase))]
    [TemplatePart(Name = "PART_PreviewBrush", Type = typeof(SolidColorBrush))]

自定义依赖项属性(propdp模板快速定义)

public static DependencyProperty ColorProperty;
public static DependencyProperty RedProperty;
public static DependencyProperty GreenProperty;
public static DependencyProperty BlueProperty;

static ColorPicker()        {            //This OverrideMetadata call tells the system that this element wants to provide a style that is different than its base class.            //This style is defined in themesgeneric.xaml            DefaultStyleKeyProperty.OverrideMetadata(typeof(ColorPicker), new FrameworkPropertyMetadata(typeof(ColorPicker)));            ColorProperty = DependencyProperty.Register("Color", typeof(Color),            typeof(ColorPicker),            new FrameworkPropertyMetadata(new PropertyChangedCallback(OnColorChanged)));            RedProperty = DependencyProperty.Register("Red", typeof(byte),                typeof(ColorPicker),                new FrameworkPropertyMetadata(new PropertyChangedCallback(OnColorRGBChanged)));            GreenProperty = DependencyProperty.Register("Green", typeof(byte),                typeof(ColorPicker),                    new FrameworkPropertyMetadata(new PropertyChangedCallback(OnColorRGBChanged)));            BlueProperty = DependencyProperty.Register("Blue", typeof(byte),                typeof(ColorPicker),                new FrameworkPropertyMetadata(new PropertyChangedCallback(OnColorRGBChanged)));        }

DefaultStyleKeyProperty.OverrideMetadata(typeof(ColorPicker), new FrameworkPropertyMetadata(typeof(ColorPicker))); 用来在themes/generic.xaml中定义默认模板.

2,自定义Command

// Set up command bindings.         CommandBinding binding = new CommandBinding(ApplicationCommands.Undo,          UndoCommand_Executed, UndoCommand_CanExecute);         this.CommandBindings.Add(binding);

private Color? previousColor;        private void UndoCommand_CanExecute(object sender, CanExecuteRoutedEventArgs e)        {            e.CanExecute = previousColor.HasValue;        }        private void UndoCommand_Executed(object sender, ExecutedRoutedEventArgs e)        {            // Use simple reverse-or-redo Undo (like Notepad).            this.Color = (Color)previousColor;        }

3,进行触发的颜色变更的跟踪

 private static void OnColorChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
        {
            ColorPicker colorPicker = (ColorPicker)sender;

            Color oldColor = (Color)e.OldValue;
            Color newColor = (Color)e.NewValue;
            colorPicker.Red = newColor.R;
            colorPicker.Green = newColor.G;
            colorPicker.Blue = newColor.B;

            colorPicker.previousColor = oldColor;
            colorPicker.OnColorChanged(oldColor, newColor);
        }

        private static void OnColorRGBChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
        {
            ColorPicker colorPicker = (ColorPicker)sender;
            Color color = colorPicker.Color;
            if (e.Property == RedProperty)
                color.R = (byte)e.NewValue;
            else if (e.Property == GreenProperty)
                color.G = (byte)e.NewValue;
            else if (e.Property == BlueProperty)
                color.B = (byte)e.NewValue;

            colorPicker.Color = color;
        }

4

5自定义RouteEvent事件

  public static readonly RoutedEvent ColorChangedEvent =
           EventManager.RegisterRoutedEvent("ColorChanged", RoutingStrategy.Bubble,
               typeof(RoutedPropertyChangedEventHandler<Color>), typeof(ColorPicker));

        public event RoutedPropertyChangedEventHandler<Color> ColorChanged
        {
            add { AddHandler(ColorChangedEvent, value); }
            remove { RemoveHandler(ColorChangedEvent, value); }
        }

        private void OnColorChanged(Color oldValue, Color newValue)
        {
            RoutedPropertyChangedEventArgs<Color> args = new RoutedPropertyChangedEventArgs<Color>(oldValue, newValue);
            args.RoutedEvent = ColorPicker.ColorChangedEvent;
            RaiseEvent(args);
        }

6,重新架构OnApply()来进行数据绑定或者别的工作

 public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();

            RangeBase slider = GetTemplateChild("PART_RedSlider") as RangeBase;
            if (slider != null)
            {
                Binding binding = new Binding("Red");
                binding.Source = this;
                binding.Mode = BindingMode.TwoWay;
                slider.SetBinding(RangeBase.ValueProperty, binding);
            }
            slider = GetTemplateChild("PART_GreenSlider") as RangeBase;
            if (slider != null)
            {
                Binding binding = new Binding("Green");
                binding.Source = this;
                binding.Mode = BindingMode.TwoWay;
                slider.SetBinding(RangeBase.ValueProperty, binding);
            }
            slider = GetTemplateChild("PART_BlueSlider") as RangeBase;
            if (slider != null)
            {
                Binding binding = new Binding("Blue");
                binding.Source = this;
                binding.Mode = BindingMode.TwoWay;
                slider.SetBinding(RangeBase.ValueProperty, binding);
            }

            SolidColorBrush brush = GetTemplateChild("PART_PreviewBrush") as SolidColorBrush;
            if (brush != null)
            {
                Binding binding = new Binding("Color");
                binding.Source = brush;
                binding.Mode = BindingMode.OneWayToSource;
                this.SetBinding(ColorPicker.ColorProperty, binding);
            }
        }
    }

7,默认的模板查看

 <Style TargetType="{x:Type local:ColorPicker}">
    <Setter Property="Template">
      <Setter.Value>
        <ControlTemplate TargetType="{x:Type local:ColorPicker}">
          <Border Background="{TemplateBinding Background}"
                  BorderBrush="{TemplateBinding BorderBrush}"
                  BorderThickness="{TemplateBinding BorderThickness}">
            <Grid>
              <Grid.RowDefinitions>
                <RowDefinition Height="Auto"></RowDefinition>
                <RowDefinition Height="Auto"></RowDefinition>
                <RowDefinition Height="Auto"></RowDefinition>
              </Grid.RowDefinitions>
              <Grid.ColumnDefinitions>
                <ColumnDefinition></ColumnDefinition>
                <ColumnDefinition Width="Auto"></ColumnDefinition>
              </Grid.ColumnDefinitions>

              <Slider Name="PART_RedSlider" Minimum="0" Maximum="255"
                       Margin="{TemplateBinding Padding}"></Slider>
              <Slider Grid.Row="1" Name="PART_GreenSlider" Minimum="0" Maximum="255"
                       Margin="{TemplateBinding Padding}"></Slider>

              <Slider Grid.Row="2" Name="PART_BlueSlider" Minimum="0" Maximum="255"
                       Margin="{TemplateBinding Padding}"></Slider>

              <Rectangle Grid.Column="1" Grid.RowSpan="3"
                         Margin="{TemplateBinding Padding}"
                         Width="50" Stroke="Black" StrokeThickness="1">
                <Rectangle.Fill>
                  <SolidColorBrush Color="{Binding Path=Color,
                       RelativeSource={RelativeSource TemplatedParent}}"></SolidColorBrush>
                </Rectangle.Fill>
              </Rectangle>

            </Grid>

          </Border>
        </ControlTemplate>
      </Setter.Value>
    </Setter>
  </Style>