WPF基础五：UI②内容元素Label_wpf label yangshi

 Label

表示控件的文本标签，并提供快捷键(access keys)支持。

此类提供对快捷键的功能和视觉支持 。 它经常用于启用对等控件的快速键盘访问 TextBox 。 若要将分配 Label 到 Control ，请将 Target 属性设置为当用户按下访问键时应获得焦点的控件。 设置目标还会导致 Microsoft UI 自动化使用标签文本作为目标控件的名称。 有关详细信息，请参阅 辅助功能。

若要设置访问密钥，请在应为访问键的字符前添加一个下划线。 如果内容有多个下划线字符，则只会将第一个下划线字符转换为访问密钥;其他下划线显示为普通文本。 如果要转换为访问键的下划线不是第一个下划线，请在要转换的下划线前面使用两个连续的下划线。 例如，以下代码包含一个访问键，并显示为 _Hello World：

<Label>__Hello_World</Label>   

由于 H 前面的下划线为2条，因此 W key 注册为访问键。

标签不可设定焦点，并且不是制表位。 有关详细信息，请参阅 焦点概述。

Label是 ContentControl ，这意味着它可以包含任何类型的单个对象 (例如字符串、图像或面板) 。 有关更多信息，请参见 ContentControl 类。

自定义标签控件

若要对多个 Label 控件应用相同的属性设置，请使用 Style 属性。 您可以修改 ControlTemplate 默认值，为控件指定独特的外观。 有关创建 ControlTemplate 的详细信息，请参阅 通过创建 System.windows.controls.controltemplate> 自定义现有控件的外观。 若要查看特定于 Label 的部分和状态，请参阅 标签样式和模板。

此控件的依赖属性可能由控件的默认样式设置。 如果按默认样式设置属性，则当控件出现在应用程序中时，属性可能会更改为默认值。 默认样式取决于应用程序运行时使用的桌面主题。 有关详细信息，请参阅 默认的 WPF 主题。

只有视觉对象属性已存在于控件的默认模板中并且已使用 TemplateBinding 设置时，设置该属性才有效。 在通过创建 ControlTemplate 自定义现有控件的外观一文的更改控件的视觉结构部分可以找到视觉属性列表。

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字段

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属性

<Label Target=" nameOfExistingElement"/>

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方法

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XAML范例

以下范例，Label控件通过助记符（快捷键：Alt+助记符）和Target属性，提供快捷方式获取控件的焦点。

下面例子：Label的First实例的快捷键是Alt+F，Label的Second实例的快捷键是Alt+S。

注册TextBox获取焦点的事件GotFocus。并提供事件的处理方法。

通过Label的快捷键使得Textbox控件获取焦点。

<Window
    x:Class="LabelDemo.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:local="clr-namespace:LabelDemo"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    Title="MainWindow"
    Width="800"
    Height="450"
    mc:Ignorable="d">
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition />
            <ColumnDefinition />
        </Grid.ColumnDefinitions>
        <StackPanel>
            <Label
                Height="40"
                HorizontalAlignment="Center"
                VerticalAlignment="Center"
                VerticalContentAlignment="Center"
                BorderBrush="Red"
                BorderThickness="2"
                Content="_First" 
                Target="{Binding  ElementName=TextBox1}"/>
            <Label
                Height="40"
                HorizontalAlignment="Center"
                VerticalAlignment="Center"
                VerticalContentAlignment="Center"
                BorderBrush="Red"
                BorderThickness="2"
                Content="_Second" 
                Target="{Binding  ElementName=TextBox2}"/>
        </StackPanel>
        <StackPanel Grid.Column="1">
            <TextBox
                x:Name="TextBox1"
                Height="40"
                HorizontalAlignment="Center"
                VerticalAlignment="Center"
                VerticalContentAlignment="Center"
                Text="TextBox1" 
                GotFocus="TextBox1_GotFocus"/>
            <TextBox
                x:Name="TextBox2"
                Height="40"
                HorizontalAlignment="Center"
                VerticalAlignment="Center"
                VerticalContentAlignment="Center"
                Text="TextBox2"
                GotFocus="TextBox2_GotFocus"/>
        </StackPanel>
 
    </Grid>
</Window>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
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 LabelDemo
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }
 
        private void TextBox1_GotFocus(object sender, RoutedEventArgs e)
        {
            MessageBox.Show((sender as TextBox).Name+ "获得焦点");
        }
 
        private void TextBox2_GotFocus(object sender, RoutedEventArgs e)
        {
            MessageBox.Show((sender as TextBox).Name + "获得焦点");
        }
    }
}

运行

当按下Alt+F，或者鼠标左键单击TextBox1等方法，使得TextBox1获取焦点后

当按下Alt+S，或者鼠标左键单击TextBox2等方法，使得TextBox2获取焦点后

UIElement.GotFocus是控件从获取焦点时触发。

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C#实例

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
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 LabelDemo
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            Grid grid = (this as Window).Content as Grid;
 
            ColumnDefinition column1 = new ColumnDefinition();
            ColumnDefinition column2 = new ColumnDefinition();
            grid.ColumnDefinitions.Add(column1);
            grid.ColumnDefinitions.Add(column2);
 
            //RowDefinition row1 = new RowDefinition();
            //RowDefinition row2 = new RowDefinition();
            //grid.RowDefinitions.Add(row1);
            //grid.RowDefinitions.Add(row2);
 
            StackPanel stackPanel1 = new StackPanel();
            StackPanel stackPanel2 = new StackPanel();
 
            Label label1 = new Label();
            Label label2 = new Label();
 
            TextBox textBox1 = new TextBox();
            TextBox textBox2 = new TextBox();
 
            AccessText _First = new AccessText();
            AccessText _Second = new AccessText();
            _First.Text = "_First";
            _Second.Text = "_Second";
 
 
            label1.Content = _First;
            label1.Target = textBox1;
            label1.Height = 40;
            label1.HorizontalAlignment = HorizontalAlignment.Center;
            label1.VerticalAlignment = VerticalAlignment.Center;
            label1.VerticalContentAlignment = VerticalAlignment.Center;
            label1.BorderBrush = Brushes.Red;
            label1.BorderThickness = new Thickness(2);
 
            label2.Content = _Second;
            label2.Target = textBox2;
            label2.Height = 40;
            label2.HorizontalAlignment = HorizontalAlignment.Center;
            label2.VerticalAlignment = VerticalAlignment.Center;
            label2.VerticalContentAlignment = VerticalAlignment.Center;
            label2.BorderBrush = Brushes.Red;
            label2.BorderThickness = new Thickness(2);
 
            textBox1.Name = "TextBox1";
            textBox1.Height = 40;
            textBox1.HorizontalAlignment = HorizontalAlignment.Center;
            textBox1.VerticalAlignment = VerticalAlignment.Center;
            textBox1.VerticalContentAlignment = VerticalAlignment.Center;
            textBox1.Text = "TextBox1";
            textBox1.GotFocus += TextBox1_GotFocus;
 
            textBox2.Name = "TextBox2";
            textBox2.Height = 40;
            textBox2.HorizontalAlignment = HorizontalAlignment.Center;
            textBox2.VerticalAlignment = VerticalAlignment.Center;
            textBox2.VerticalContentAlignment = VerticalAlignment.Center;
            textBox2.Text = "TextBox2";
            textBox2.GotFocus += TextBox2_GotFocus;
 
            stackPanel1.Children.Add(label1);
            stackPanel1.Children.Add(label2);
 
            stackPanel2.Children.Add(textBox1);
            stackPanel2.Children.Add(textBox2);
 
            grid.Children.Add(stackPanel1);
            grid.Children.Add(stackPanel2);
 
            Grid.SetColumn(stackPanel2,1);
        }
 
        private void TextBox1_GotFocus(object sender, RoutedEventArgs e)
        {
            MessageBox.Show((sender as TextBox).Name+ "获得焦点");
 
        }
 
        private void TextBox2_GotFocus(object sender, RoutedEventArgs e)
        {
            MessageBox.Show((sender as TextBox).Name + "获得焦点");
        }
    }
}