[英]Binding a property with another property owned to a user control
我想實現幾個屬性之間的綁定。 可能嗎 ?
我有一個名為“ MainWindow”的主窗口類,它具有一個屬性“ InputText”。 此類包含一個名為MyUserControl的用戶控件。 MyUserControl具有綁定到依賴項屬性“ MyTextProperty”的文本框
我想將主窗口的屬性“ InputText”與用戶控件的依賴項屬性“ MyTextProperty”綁定在一起。 因此,如果用戶編寫文本,則希望更新屬性“ InputText”,“ MyTextProperty”,“ MyText”。
用戶控制代碼:
using System;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.ComponentModel;
namespace WpfApplication1
{
/// <summary>
/// Interaction logic for MyUserControl.xaml
/// </summary>
public partial class MyUserControl : UserControl
{
public string MyText
{
get { return (string)GetValue(MyTextProperty); }
set { SetValue(MyTextProperty, value); }
}
public static readonly DependencyProperty MyTextProperty =
DependencyProperty.Register("MyText", typeof(string), typeof(MyUserControl), new PropertyMetadata(0));
public MyUserControl()
{
this.DataContext = this;
InitializeComponent();
}
public event PropertyChangedEventHandler PropertyChanged;
protected void NotifyPropertyChanged(string property)
{
if (this.PropertyChanged != null)
{
this.PropertyChanged.Invoke(this, new PropertyChangedEventArgs(property));
}
}
}
}
WPF用戶控制代碼:
<UserControl x:Class="WpfApplication1.MyUserControl"
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"
mc:Ignorable="d"
d:DesignHeight="25 " d:DesignWidth="100"
Background="Black">
<Grid>
<TextBox Height="20" Width="100" Text="{Binding MyText}"></TextBox>
</Grid>
</UserControl>
主窗口代碼:
using System;
using System.Linq;
using System.Windows;
using System.ComponentModel;
namespace WpfApplication1
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window, INotifyPropertyChanged
{
private string inputText;
public string InputText
{
get { return inputText; }
set
{
inputText = value;
NotifyPropertyChanged("InputText");
}
}
public MainWindow()
{
this.DataContext = this;
InitializeComponent();
}
public event PropertyChangedEventHandler PropertyChanged;
protected void NotifyPropertyChanged(String property)
{
if (this.PropertyChanged != null)
{
this.PropertyChanged.Invoke(this, new PropertyChangedEventArgs(property));
}
}
}
}
WPF主窗口代碼:
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:myNS="clr-namespace:WpfApplication1"
Title="MainWindow" Height="80" Width="300">
<Grid>
<StackPanel Orientation="Vertical">
<myNS:MyUserControl x:Name="test" MyText="{Binding InputText}"></myNS:MyUserControl>
<Button Name="cmdValidation" Content="Validation" Height="20"></Button>
</StackPanel>
</Grid>
</Window>
謝謝 !
如果您希望發布的代碼盡可能少地更改,那么:
在MainWindow.xaml中,更改
MyText="{Binding InputText}"
至
MyText="{Binding RelativeSource={RelativeSource AncestorType=Window}, Path=DataContext.InputText, Mode=TwoWay}"
如果要UC更新InputText,則需要TwoWay。
同樣,在MyUserControl.xaml.cs的DependencyProperty.Register語句中,將字符串的PropertyMetadata默認值設置為0 -將其更改為適合字符串的值-如null或string.empty。
public static readonly DependencyProperty MyTextProperty =
DependencyProperty.Register("MyText", typeof(string), typeof(MyUserControl), new PropertyMetadata(null));
如果您想稍微修改一下代碼,可以通過以下方式在用戶控件中使其更復雜,但在使用時更簡單:
默認情況下,使依賴項屬性MyText綁定兩種方式
停止在用戶控件中設置DataContext
更改UC xaml文本綁定以使用UC的相對源
我總是覺得代碼更容易理解,因此這里是文件的修改版本:MainWindow.xaml
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:myNS="clr-namespace:WpfApplication1"
Title="MainWindow" Height="180" Width="300">
<Grid>
<StackPanel Orientation="Vertical">
<TextBlock>
<Run Text="MainWindow.InputText: " />
<Run Text="{Binding InputText}" />
</TextBlock>
<TextBlock>
<Run Text="MyUserControl.MyText: " />
<Run Text="{Binding ElementName=test, Path=MyText}" />
</TextBlock>
<myNS:MyUserControl x:Name="test" MyText="{Binding InputText}"></myNS:MyUserControl>
<Button Name="cmdValidation" Content="Validation" Height="20"></Button>
</StackPanel>
</Grid>
</Window>
MainWindow.xaml.cs
using System;
using System.Windows;
using System.ComponentModel;
namespace WpfApplication1
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window, INotifyPropertyChanged
{
private string inputText = "Initial Value";
public string InputText
{
get { return inputText; }
set
{
inputText = value;
NotifyPropertyChanged("InputText");
}
}
public MainWindow()
{
this.DataContext = this;
InitializeComponent();
}
public event PropertyChangedEventHandler PropertyChanged;
protected void NotifyPropertyChanged(String property)
{
if (this.PropertyChanged != null)
{
this.PropertyChanged.Invoke(this, new PropertyChangedEventArgs(property));
}
}
}
}
MyUserControl.xaml
<UserControl x:Class="WpfApplication1.MyUserControl"
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"
mc:Ignorable="d"
d:DesignHeight="25 " d:DesignWidth="100"
Background="Black">
<Grid>
<TextBox Height="20" Width="100" Text="{Binding RelativeSource={RelativeSource AncestorType=UserControl}, Path=MyText, UpdateSourceTrigger=PropertyChanged}"></TextBox>
</Grid>
</UserControl>
MyUserControl.xaml.cs
using System.Windows;
using System.Windows.Controls;
namespace WpfApplication1
{
/// <summary>
/// Interaction logic for MyUserControl.xaml
/// </summary>
public partial class MyUserControl : UserControl
{
public string MyText
{
get { return (string)GetValue(MyTextProperty); }
set { SetValue(MyTextProperty, value); }
}
public static readonly DependencyProperty MyTextProperty =
DependencyProperty.Register("MyText", typeof(string), typeof(MyUserControl), new FrameworkPropertyMetadata(null) { BindsTwoWayByDefault = true });
public MyUserControl()
{
InitializeComponent();
}
}
}
首先,
this.DataContext = this;
不就是不。 您正在通過其父窗口覆蓋UserControl
設置的DataContext
。
對於您的UserControl
,給它一個x:Name
,然后直接綁定到依賴項屬性。
<UserControl
...
x:Name="usr">
<TextBox Text="{Binding MyText, ElementName=usr}" ... />
完成此操作后,您只需將MyText
屬性綁定到MainWindow
的DataContext
。
<myNS:MyUserControl x:Name="test" MyText="{Binding InputText}" />
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