Silverlight - 绑定(bind)控制 borderthickness

Question

我试图更好地理解 Silverlights 绑定(bind)机制，因此创建了一个简单的程序，可以在按下按钮时更改列表框的 borderthickness。但是它不起作用，我无法弄清楚我做错了什么。有什么想法吗？

XAML:

<Grid x:Name="LayoutRoot" Background="White">
    <ListBox Height="100" HorizontalAlignment="Left" Margin="134,102,0,0" Name="listBox1" VerticalAlignment="Top" Width="120" BorderThickness="{Binding TheThickness, Mode=TwoWay}" />
    <Button Content="Button" Height="23" HorizontalAlignment="Left" Margin="276,36,0,0" Name="button1" VerticalAlignment="Top" Width="75" Click="button1_Click" />
</Grid>

代码:

using System.ComponentModel;
using System.Windows;
using System.Windows.Controls;

namespace SilverlightApplication4
{
    public partial class MainPage : UserControl
    {
        private TestClass testInst = new TestClass(); 

        public MainPage()

    {
        InitializeComponent();
        listBox1.DataContext = testInst;
    }

    private void button1_Click(object sender, RoutedEventArgs e)
    {
        testInst.TheThickness = 10;
    }
}

public class TestClass
{
    private int theThickness = 5;

    public int TheThickness
    {
        get { return theThickness; }
        set
        {
            theThickness = value;

            NotifyPropertyChanged("TheThickness");
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    // NotifyPropertyChanged will raise the PropertyChanged event, passing the source property that is being updated.
    private void NotifyPropertyChanged(string propertyName)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

Answer 1

边框厚度的类型为 Thickness，它有多个 Top、Bottom、Left 和 Right 值。 XAML 解析器知道如何正确处理 BorderThickness="5"之类的内容，但在代码中您需要使用 Thickness 类型。例如:-

public Thickness SelectedThickness
{
    get { return (Thickness)GetValue(SelectedThicknessProperty); }
    set { SetValue(SelectedThicknessProperty, value); }
}

public static readonly DependencyProperty SelectedThicknessProperty =
    DependencyProperty.Register("SelectedThickness", typeof(Thickness), typeof(MyRectangle),
    new PropertyMetadata(new Thickness() { Top = 1, Bottom = 1, Left = 1, Right = 1 }));
}

在这种情况下，默认厚度为 1。

编辑 更像您的代码:-

    private Thickness theThickness = new Thickness() {Left = 5, Right = 5, Top = 5, Bottom = 5};

    public Thickness TheThickness
    {
        get { return theThickness; }
        set
        {
            theThickness = value;

            NotifyPropertyChanged("TheThickness");
        }
    }