WPF 构建无外观(Lookless)控件

构建一个用户可以使用Template属性设置外观的WPF控件需要以下几步

  1. 1、继承自System.Windows.Controls.Control
    2、设置DefaultStyleKeyProperty
    3、实现控件功能
  2. 4、定义默认Sytle
  3. 5、添加ThemeInfo
    我借用一个时钟的控件例子,讲解以下每一个步骤
  4. 第1步 继承自System.Windows.Controls.Control

 

我们的自定义控件继承自System.Windows.Controls.Control,如果有更特别的控件,也可以继承自更复杂的控件。

类声明

   1: public class Clock : Control
   2: {
   3: }

 

第2步 设置DefaultStyleKeyProperty

 

无外观的控件需要在静态构造函数中设置DefaultStyleKeyProperty,这样它会去在themes/generic.xaml的文件获取默认的样式。

   1: static Clock()
   2: {
   3:     DefaultStyleKeyProperty.OverrideMetadata(typeof(Clock), new FrameworkPropertyMetadata(typeof(Clock)));
   4: }

第3步 实现控件功能

这一步没什么特别的,就是内部有个DateTime类型和一个DispatcherTimer,完成一个时钟的功能

   1: public class Clock : Control
   2: {
   3:     private DispatcherTimer timer;
   4:  
   5:     static Clock()
   6:     {
   7:         DefaultStyleKeyProperty.OverrideMetadata(typeof(Clock), new FrameworkPropertyMetadata(typeof(Clock)));
   8:     }
   9:  
  10:     protected override void OnInitialized(EventArgs e)
  11:     {
  12:         base.OnInitialized(e);
  13:  
  14:         UpdateDateTime();
  15:  
  16:         timer = new DispatcherTimer();
  17:         timer.Interval = TimeSpan.FromMilliseconds(1000 - DateTime.Now.Millisecond);
  18:         timer.Tick += new EventHandler(Timer_Tick);
  19:         timer.Start();
  20:     }
  21:  
  22:     private void Timer_Tick(object sender, EventArgs e)
  23:     {
  24:         UpdateDateTime();
  25:  
  26:         timer.Interval = TimeSpan.FromMilliseconds(1000 - DateTime.Now.Millisecond);
  27:         timer.Start();
  28:     }
  29:  
  30:     private void UpdateDateTime()
  31:     {
  32:         this.DateTime = System.DateTime.Now;
  33:     }
  34:  
  35:     public DateTime DateTime
  36:     {
  37:         get
  38:         {
  39:             return (DateTime)GetValue(DateTimeProperty);
  40:         }
  41:         private set
  42:         {
  43:             SetValue(DateTimeProperty, value);
  44:         }
  45:     }
  46:  
  47:     public static DependencyProperty DateTimeProperty = DependencyProperty.Register(
  48:             "DateTime",
  49:             typeof(DateTime),
  50:             typeof(Clock),
  51:             new PropertyMetadata(DateTime.Now, new PropertyChangedCallback(OnDateTimeInvalidated)));
  52:  
  53:     public static readonly RoutedEvent DateTimeChangedEvent =
  54:         EventManager.RegisterRoutedEvent("DateTimeChanged", RoutingStrategy.Bubble, typeof(RoutedPropertyChangedEventHandler<DateTime>), typeof(Clock));
  55:  
  56:     protected virtual void OnDateTimeChanged(DateTime oldValue, DateTime newValue)
  57:     {
  58:         RoutedPropertyChangedEventArgs<DateTime> args = new RoutedPropertyChangedEventArgs<DateTime>(oldValue, newValue);
  59:         args.RoutedEvent = Clock.DateTimeChangedEvent;
  60:         RaiseEvent(args);
  61:     }
  62:  
  63:     private static void OnDateTimeInvalidated(DependencyObject d, DependencyPropertyChangedEventArgs e)
  64:     {
  65:         Clock clock = (Clock)d;
  66:  
  67:         DateTime oldValue = (DateTime)e.OldValue;
  68:         DateTime newValue = (DateTime)e.NewValue;
  69:  
  70:         clock.OnDateTimeChanged(oldValue, newValue);
  71:     }
  72: }

 

第4步 定义默认Sytle

 

如上所述,我们还需要一个默认的Template,它写在themes/generic.xaml文件中,这个文件可能需要自己创建

   1: <ResourceDictionary
   2:     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
   3:     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
   4:     xmlns:local="clr-namespace:CustomControlLibrary"
   5:     >
   6:  
   7:     <Style TargetType="{x:Type local:Clock}">
   8:         <Setter Property="Template">
   9:             <Setter.Value>
  10:                 <ControlTemplate TargetType="{x:Type local:Clock}">
  11:                     <TextBlock Text="{Binding Path=DateTime, RelativeSource={RelativeSource TemplatedParent}}" />
  12:                 </ControlTemplate>
  13:             </Setter.Value>
  14:         </Setter>
  15:     </Style>
  16: </ResourceDictionary>
这里要注意TargetType的使用。到这里控件还是不能找到默认的模板,还需要下面的最后一步

 

  1. 第5步 添加ThemeInfo

 

最后还需要在AssemblyInfo.cs文件中加入ThemeInfo信息,在文件中加入以下特性

   1: [assembly: ThemeInfo(
   2:     ResourceDictionaryLocation.None,
   3:     ResourceDictionaryLocation.SourceAssembly
   4: )]

 

  1. 附注

 

如果需要在模板中使用特定的元素名,来或许模板中的某个特定控件,还有几个地方需要注意。

1、模板内的Name最好以PART开头,好的名称类似于PART_TextBox

2、获取Template中控件的代码,需要重载OnApplyTemplate()方法,可以使用GetTemplateChild方法获取,如下
   1: public override void OnApplyTemplate()
   2: {
   3:     base.OnApplyTemplate();
   4:  
   5:     //从模板中获取名称为PART_PresentationTextBox的TextBox
   6:     _presentationTextBox = GetTemplateChild("PART_PresentationTextBox") as TextBox;
   7:     if(_presentationTextBox != null)
   8:     {
   9:         //对_presentationTextBox进行操作
  10:     }
  11: }

3、在控件类添加TemplatePart

   1: [TemplatePart(Name = "PART_PresentationTextBox", Type = typeof(TextBox))]
   2: public class TimeSpanPicker:Control

这个内容可以参考https://gitcafe.com/atskyline/WPFTimeSpanPickerControl

  1. 参考资料

 

http://www.codeproject.com/Articles/14340/Creating-a-look-less-custom-control-in-WPF

http://www.codeproject.com/Articles/35444/Defining-the-Default-Style-for-a-Lookless-Control

posted @ 2012-11-16 19:20  atskyline  阅读(6047)  评论(4编辑  收藏  举报