任务:实现最简单的依赖属性,可以在xaml中像这样使用:
<uc:MyUserControl1 MyTextProperty="{Binding Text}"/>
我认为这个答案非常接近,为了更好地可读性,我在此处复制了大部分代码(主要是上面的答案)。
<UserControl x:Class="Test.UserControls.MyUserControl1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
DataContext="{Binding RelativeSource={RelativeSource Self}}">
<Grid>
<!-- Text is being bound to outward representative property;
Note the DataContext of the UserControl -->
<TextBox Text="{Binding MyTextProperty}"/>
</Grid>
</UserControl>
并且
public partial class MyUserControl1 : UserControl
{
// The dependency property which will be accessible on the UserControl
public static readonly DependencyProperty MyTextPropertyProperty =
DependencyProperty.Register("MyTextProperty", typeof(string), typeof(MyUserControl1), new UIPropertyMetadata(String.Empty));
public string MyTextProperty
{
get { return (string)GetValue(MyTextPropertyProperty); }
set { SetValue(MyTextPropertyProperty, value); }
}
public MyUserControl1()
{
InitializeComponent();
}
}
这是我的MainWindow.xaml文件。
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:uc="clr-namespace:WpfApplication1"
Title="MainWindow" Height="350" Width="525">
<StackPanel Orientation="Vertical">
<uc:MyUserControl1 MyTextProperty="my text goes here"/>
<Button Click="ButtonBase_OnClick" Content="click"/>
</StackPanel>
</Window>
目前,一切正常。然而,我觉得这并不太有用。我需要的是:
<uc:MyUserControl1 MyTextProperty="{Binding Text}"/>
通过设置 DataContext
(通常在 MVVM 中执行)来实现对此进行更改。
所以我将上述行替换,并添加以下代码:
public partial class MainWindow : Window, INotifyPropertyChanged
{
public MainWindow()
{
InitializeComponent();
Text = "Initial Text";
DataContext = this;
}
private string _Text;
public string Text
{
get { return _Text; }
set
{
if (value != _Text)
{
_Text = value;
NotifyPropertyChanged("Text");
}
}
}
private void ButtonBase_OnClick(object sender, RoutedEventArgs e)
{
Text = "clicked";
}
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged(String info)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(info));
}
}
}
“初始文本”和“点击”都没有显示……从来没有。所以我的问题是如何正确实现dept属性,以便与之一起使用。
<uc:MyUserControl1 MyTextProperty="{Binding Text}"/>