数据在WPF用户控件绑定 [英] Data Binding in WPF User Controls

问题描述

我创造了一系列由几个窗口共享控件的用户控件。一项所述的控制是一个标签表示在协议编号

I am creating a UserControl for a series of controls shared by several windows. One of the controls is a Label which shows the flow of some other process in terms of "protocol numbers".

我想提供数据绑定这个标签，这样的窗口会自动反映过程为协议数量变量的变化的状态。

I am trying to offer DataBinding with this Label so the Window automatically reflects the state of the process as the protocol number variable changes.

这是用户控制的XAML：

This is the User control XAML:

<UserControl Name="MainOptionsPanel"
    x:Class="ExperienceMainControls.MainControls"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    DataContext="{Binding RelativeSource={RelativeSource Self}}"
    >
<Label Height="Auto" Name="numberLabel">Protocol:</Label>
<Label Content="{Binding Path=ProtocolNumber}" Name="protocolNumberLabel"/>
(...)
</UserControl>

这是code-背后：

And this is the Code-Behind:

public partial class MainControls 
{
    public MainControls()
    {
        InitializeComponent();
    }

    public int ProtocolNumber
    {
        get { return (int)GetValue(ProtocolNumberProperty); }
        set { SetValue(ProtocolNumberProperty, value); }
    }

    public static DependencyProperty ProtocolNumberProperty = 
       DependencyProperty.Register("ProtocolNumber", typeof(int), typeof(MainControls));
}

这似乎是工作，因为如果在构造函数中我设置ProtocolNumber为任意值，它反映在用户的控制。

This seems to be working because if on the constructor I set ProtocolNumber to an arbitrary value, it is reflected in the user control.

不过，最后的窗口中使用这个用户控件时，数据绑定符。

However, when using this usercontrol on the final window, the data binding breaks.

XAML：

<Window x:Class="UserControlTesting.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:expControl="clr-namespace:ExperienceMainControls;assembly=ExperienceMainControls"
    DataContext="{Binding RelativeSource={RelativeSource Self}}"
    >
    <StackPanel>
        <expControl:MainControls ProtocolNumber="{Binding Path=Number, Mode=TwoWay}" />
    </StackPanel>

</Window>

code-背后的窗口：

Code-Behind for window:

public partial class Window1 : Window
{
    public Window1()
    {
        Number= 15;
        InitializeComponent();
    }

    public int Number { get; set; }
}

此设置协议编号为零，忽略设置数的值。

This sets the Protocol Number to zero, ignoring the value set to Number.

我读过的例子

推荐答案

如果你看看你的输出窗口，你应该看到绑定例外。

if you look at your output window you should see the binding exception.

你的问题是以下几点：你的用户控件中，您将标签绑定到用户控件的DP ProtocolNumber而不是的DataContext ，所以你必须增加对例如元素名称的结合。

The problem you have is the following: within your usercontrol you will bind the label to the DP ProtocolNumber of your usercontrol and not the DataContext, so you have to add for example the element name to the binding.

<UserControl Name="MainOptionsPanel"
    x:Class="ExperienceMainControls.MainControls"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    x:Name="uc"
    >
<Label Height="Auto" Name="numberLabel">Protocol:</Label>
<Label Content="{Binding Path=ProtocolNumber, ElementName=uc}" Name="protocolNumberLabel"/>
(...)
</UserControl>

编辑：清理一些东西，如果你改变你的主窗口绑定你的用户控件也有效。但你必须绑定到主窗口的DataContext的用的RelativeSource。

to clear some things up, your usercontrol also works if you change the binding in your MainWindow. but you have to bind to the DataContext of the MainWindow with RelativeSource.

    <expControl:MainControls ProtocolNumber="{Binding Path=Number, RelativeSource={RelativeSource AncestorType={x:Type Window}}}" />

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