Silverlight的用户控件自定义属性绑定 [英] Silverlight UserControl Custom Property Binding
问题描述
什么是落实在Silverlight用户控件自定义属性的正确方法？
What is the proper way to implement Custom Properties in Silverlight UserControls?
每页在Silverlight在技术上是一个用户控件（它们是从用户控件类派生）。当我在这里说的用户控件，我的意思是一个自定义用户控件，将许多不同页面内使用在许多不同的场景（类似于ASP.NET用户控件）。
Every "Page" in Silverlight is technically a UserControl (they are derived from the UserControl class). When I say UserControl here, I mean a Custom UserControl that will be used inside many different pages in many different scenarios (similar to an ASP.NET UserControl).
我想自定义用户控件支持绑定和不依赖于该物业被绑定到名称，始终是相同的。相反，我希望用户控件本身具有的用户控件绑定到内部的控件和的ViewModels的用户控件外还绑定属性。 （请参见下面的示例）
I would like the Custom UserControl to support Binding and not rely on the Name of the Property it is binding to, to always be the same. Instead, I would like the UserControl itself to have a property that the Controls inside the UserControl bind to, and the ViewModels outside the UserControl also bind to. (please see the example below)
在用户控件中绑定的工作原理，在内部的MainPage绑定工作，我成立了和的MainPage用户控件之间的不工作的结合。特别是这一行：
Binding within the UserControl works, Binding within the MainPage works, The Binding I set up between the MainPage and the UserControl does not work. Specifically this line:
<myUserControls:MyCustomUserControl x:Name="MyCustomControl2"
SelectedText="{Binding MainPageSelectedText, Mode=TwoWay}"
Width="200" Height="50" />
示例输出：结果
example output:
MainPage.xaml中
MainPage.xaml
<UserControl x:Class="SilverlightCustomUserControl.MainPage"
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:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:myUserControls="clr-namespace:SilverlightCustomUserControl"
mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="480"
DataContext="{Binding RelativeSource={RelativeSource Self}}">
<Canvas x:Name="LayoutRoot">
<StackPanel Orientation="Vertical">
<TextBlock Text="UserControl Binding:" Width="200"></TextBlock>
<myUserControls:MyCustomUserControl x:Name="MyCustomControl2" SelectedText="{Binding MainPageSelectedText, Mode=TwoWay}" Width="200" Height="50" />
<TextBlock Text="MainPage Binding:" Width="200"></TextBlock>
<TextBox Text="{Binding MainPageSelectedText, Mode=TwoWay}" Width="200"></TextBox>
<Border BorderBrush="Black" BorderThickness="1">
<TextBlock Text="{Binding MainPageSelectedText}" Width="200" Height="24"></TextBlock>
</Border>
</StackPanel>
</Canvas>
</UserControl>
MainPage.xaml.cs中
MainPage.xaml.cs
namespace SilverlightCustomUserControl
{
public partial class MainPage : UserControl, INotifyPropertyChanged
{
//NOTE: would probably be in a ViewModel
public string MainPageSelectedText
{
get { return _MainPageSelectedText; }
set
{
string myValue = value ?? String.Empty;
if (_MainPageSelectedText != myValue)
{
_MainPageSelectedText = value;
OnPropertyChanged("MainPageSelectedText");
}
}
}
private string _MainPageSelectedText;
public MainPage()
{
InitializeComponent();
}
#region INotifyPropertyChanged Members
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged(string name)
{
PropertyChangedEventHandler ph = this.PropertyChanged;
if (ph != null)
ph(this, new PropertyChangedEventArgs(name));
}
#endregion
}
}
MyCustomUserControl.xaml
MyCustomUserControl.xaml
<UserControl
x:Class="SilverlightCustomUserControl.MyCustomUserControl"
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:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
DataContext="{Binding RelativeSource={RelativeSource Self}}">
<Grid>
<StackPanel>
<TextBox Text="{Binding SelectedText, Mode=TwoWay}" />
<Border BorderBrush="Black" BorderThickness="1">
<TextBlock Text="{Binding SelectedText}" Height="24"></TextBlock>
</Border>
</StackPanel>
</Grid>
</UserControl>
MyCustomUserControl.xaml.cs
MyCustomUserControl.xaml.cs
namespace SilverlightCustomUserControl
{
public partial class MyCustomUserControl : UserControl
{
public string SelectedText
{
get { return (string)GetValue(SelectedTextProperty); }
set { SetValue(SelectedTextProperty, value); }
}
public static readonly DependencyProperty SelectedTextProperty =
DependencyProperty.Register("SelectedText", typeof(string), typeof(MyCustomUserControl), new PropertyMetadata("", SelectedText_PropertyChangedCallback));
public MyCustomUserControl()
{
InitializeComponent();
}
private static void SelectedText_PropertyChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
//empty
}
}
}
参考（我是如何走到这一步）：
References (how I got this far):
使用DependencyPropertys：
<一href=\"http://geekswithblogs.net/thibbard/archive/2008/04/22/wpf-custom-control-dependency-property-gotcha.aspx\" rel=\"nofollow\">http://geekswithblogs.net/thibbard/archive/2008/04/22/wpf-custom-control-dependency-property-gotcha.aspx
use DependencyPropertys: http://geekswithblogs.net/thibbard/archive/2008/04/22/wpf-custom-control-dependency-property-gotcha.aspx
使用DependencyPropertys，添加X：命名你的用户控件 - 在PropertyChangedCallback方法再次添加绑定使用的ElementName，设置自定义属性：
<一href=\"http://stackoverflow.com/questions/845564/setting-custom-properties-in-usercontrol-via-databinding\">Setting通过数据绑定在用户控件自定义属性
use DependencyPropertys, add x:Name to your UserControl - add Binding with ElementName, set Custom property again in the PropertyChangedCallback method: Setting Custom Properties in UserControl via DataBinding
不要使用自定义属性，依靠底层的datacontext的名字（我不喜欢这个解决方案）：
<一href=\"http://stackoverflow.com/questions/1145435/wpf-trouble-using-dependency-properties-in-a-usercontrol\">wpf在用户控件使用依赖属性麻烦
don't use custom properties, rely on underlying datacontext names (I do not like this solution): wpf trouble using dependency properties in a UserControl
推荐答案
我把它理解为你的控制没有收到来自残废页的新值的原因是，要设置控件的DataContext的。如果你没有那么控制的的DataContext将其父在这种情况下继承，主页。
I understand it as the reason your control is not receiving the new value from the maim page is that you are setting the DataContext of the control. If you hadn't then the control's DataContext will be inherited from its parent, the main page in this case.
要得到这个工作，我删除你控制的DataContext的设置，增加了一个X：名称给每个控制和使用[名] .SetBinding方法设置控件的构造函数的结合
To get this to work I removed you control's DataContext setting, added an x:Name to each control and set the binding in the constructor of the control using the [name].SetBinding method.
我确实在构造函数的结合，因为我无法弄清楚设置声明绑定的Source属性在XAML以自我的一种方式。即{[这里自一些如何]绑定SelectedText，模式=双向，源=}。我曾尝试使用的RelativeSource = {自我的RelativeSource}没有快乐。
I did the binding in the ctor as I couldn't figure out a way of setting the Source property of the declarative binding in the xaml to Self. i.e. {Binding SelectedText, Mode=TwoWay, Source=[Self here some how]}. I did try using RelativeSource={RelativeSource Self} with no joy.
请注意：这一切都是SL3
NOTE: All this is SL3.
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