访问ControlTemplate内部的元素
需要用到code behind
注意要给需要访问的元素命名x:Name="PART_TextBlock"
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:CustomControlLib"> <Style TargetType="{x:Type local:MyControl}"> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="{x:Type local:MyControl}"> <Border Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}"> <StackPanel> <TextBlock x:Name="PART_TextBlock" /> </StackPanel> </Border> </ControlTemplate> </Setter.Value> </Setter> </Style> </ResourceDictionary>
custom control的程序部分
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Windows; using System.Windows.Controls; using System.Windows.Data; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Imaging; using System.Windows.Navigation; using System.Windows.Shapes; namespace CustomControlLib { public class MyControl : Button { private const string TextBlockPart = "PART_TextBlock"; TextBlock textBlock; static MyControl() { DefaultStyleKeyProperty.OverrideMetadata(typeof(MyControl), new FrameworkPropertyMetadata(typeof(MyControl))); } public override void OnApplyTemplate() //OnApplyTemplate get called everytime a template is applied to the control,control update { base.OnApplyTemplate(); //Button有自己的OnApplyTemplate我们需要call这个beofre call我们自己写的OnApplyTemplate方法 if (textBlock != null) //避免memory leak每次call OnApplyTemplate方法时都给同一个textBlock加上event { textBlock.TextInput -= new TextCompositionEventHandler(textBlock_TextInput); } textBlock = GetTemplateChild(TextBlockPart) as TextBlock; if (textBlock != null) { textBlock.Text = "Set from code"; textBlock.TextInput +=new TextCompositionEventHandler(textBlock_TextInput); } } private void textBlock_TextInput(object sender, TextCompositionEventArgs e) { } } }
使用该control
<Window x:Class="CustomControlDemo.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:cc="clr-namespace:CustomControlLib;assembly=CustomControlLib" Title="MainWindow" Width="525" Height="350"> <Grid> <cc:MyControl /> </Grid> </Window>
改进：上面的方法不好，设想如果controlTemaplte里有很多element都需要访问，每一个元素都需要后台程序这样访问的话，会很乱
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Windows; using System.Windows.Controls; using System.Windows.Data; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Imaging; using System.Windows.Navigation; using System.Windows.Shapes; namespace CustomControlLib { [TemplatePart(Name = TextBlockPart, Type = typeof(TextBlock))] //告诉使用template的作者这里x:Name为PART_TextBlock的control一定要是TextBlock类型的 public class MyControl : Button { private const string TextBlockPart = "PART_TextBlock"; TextBlock _textBlock; //避免每一次call OnApplyTemplate都在方法体里创建一个TextBlock，在方法前定义一个变量来储存 protected TextBlock TextBlock { get {return _textBlock; } set { if (_textBlock != null) //避免memory leak每次call OnApplyTemplate方法时都给同一个textBlock加上event { _textBlock.TextInput -= new TextCompositionEventHandler(textBlock_TextInput); } _textBlock = value; if (_textBlock != null) { _textBlock.Text = "Set from code"; _textBlock.TextInput += new TextCompositionEventHandler(textBlock_TextInput); } } } static MyControl() { DefaultStyleKeyProperty.OverrideMetadata(typeof(MyControl), new FrameworkPropertyMetadata(typeof(MyControl))); } public override void OnApplyTemplate() //OnApplyTemplate get called everytime a template is applied to the control,control update { base.OnApplyTemplate(); //Button有自己的OnApplyTemplate我们需要call这个beofre call我们自己写的OnApplyTemplate方法 TextBlock = GetTemplateChild(TextBlockPart) as TextBlock; //每次call都赋值属性 } private void textBlock_TextInput(object sender, TextCompositionEventArgs e) { } } }
TemplatePart(Name="PART_Decrease", Type=typeof(RepeatButton))
一直没明白这是干嘛用的，搜了一下，记载一下。
以Button的定义为例：
namespace System.Windows.Controls { // Summary: // Represents a button control, which reacts to the Click event. [TemplatePart(Name = "Normal State", Type = typeof(Storyboard))] [TemplatePart(Name = "MouseOver State", Type = typeof(Storyboard))] [TemplatePart(Name = "RootElement", Type = typeof(FrameworkElement))] [TemplatePart(Name = "Pressed State", Type = typeof(Storyboard))] [TemplatePart(Name = "FocusVisualElement", Type = typeof(UIElement))] [TemplatePart(Name = "Disabled State", Type = typeof(Storyboard))] public class Button : ButtonBase { // Summary: // Initializes a new instance of the Button class. public Button(); // Summary: // Apply a template to the Button. protected override void OnApplyTemplate(); // // Summary: // Called when the IsEnabled property changes. // // Parameters: // isEnabled: // New value of the IsEnabled property. protected override void OnIsEnabledChanged(bool isEnabled); } }
[TemplatePart(Name = "Normal State", Type = typeof(Storyboard))] 这种东东是做什么用的 ， 其实这是一种契约 ， 是一种推荐的控件设计模式（只是推荐） ， 意思是告诉要来写ControlTemplate的用户 ， 你的ControlTemplate中需要有一个x:Name为“Normal State” , 类型为Storyboard ， 当然这个类型可以是继承来的， 为什么一定要包含这些契约规定的元素 ， 因为逻辑部分对这些东西进行了引用，它们将对控件的默认行为起着关键作用， 可以理解为这个控件的最基本元素 ， 是实现默认行为的最小集合， 自然，你的ControlTemplate中如果没有包含契约中的内容 ， 则相应的逻辑将无法实现。
所以说白了，就是提示用的.....这么写比较规范。
