Question

我需要从用户Control(一个包含文字箱和清单箱的电网:我需要在这份清单箱中添加一些内容)中获取我在森林基金中创建的集装箱数据目录:这是这样做的最佳方式?

我正想把数据内容作为参数通过用户控制,但认为这样做有更清洁的方法。

Answer 1

Normally the DataContext will be inherited, just do not explicitly set it on the UserControl and it will get it from its parent. If you have to set it you could still use the Parent property to get the parent, which you then can safe-cast to a FrameworkElement and if it is not null you can grab its DataContext.

Answer 2

I sometimes have nested User controls and a grandchild usercontrol sometimes needs the grandparent s view s data context. The easiest way I have found so far (and I m somewhat of a newbie) is to use the following:

<Shared:GranchildControl DataContext="{Binding RelativeSource={RelativeSource 
                    FindAncestor, AncestorType={x:Type GrandparentView}},
                    Path=DataContext.GrandparentViewModel}" />

我写了

Answer 3

在您的项目中添加这一具有约束力的表格:

using System.Windows;

namespace YourNameSpace
{
    /// <summary>
    /// Add Proxy <ut:BindingProxy x:Key="Proxy" Data="{Binding}" /> to Resources
    /// Bind like <Element Property="{Binding Data.MyValue, Source={StaticResource Proxy}}" />   
    /// </summary>
    public class BindingProxy : Freezable
    {
        protected override Freezable CreateInstanceCore()
        {
            return new BindingProxy();
        }

        public object Data
        {
            get { return (object)GetValue(DataProperty); }
            set { SetValue(DataProperty, value); }
        }

        public static readonly DependencyProperty DataProperty = DependencyProperty.Register("Data", typeof(object), typeof(BindingProxy));
    }
}

Add the BindingProxy to your UserControl s resources.
Set the Data property of the BindingProxy to whatever you need, e.g. search for a parent Window. Data="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}},Path=DataContext}" If you needed something more complex you could use a custom converter.

现在,您可以查阅该母体的数据。资料来源:统计局。编码

<UserControl 
         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"
         xmlns:common="clr-namespace:YourNameSpace;assembly=YourAssembly"
         mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="300">
    <UserControl.Resources>
        <common:BindingProxy x:Key="BindingProxy" Data="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}},Path=DataContext}" />
    </UserControl.Resources>
    <Border>
        <Button Command="{Binding Data.MyCommand, Source={StaticResource BindingProxy}}">Execute My Command</Button>
        <!-- some visual stuff -->
    </Border>
</UserControl>

Answer 4

H.B.在标题中回答了问题。

但案文提出了不同的设计问题。我请你重新考虑你的设计。

A control inherits the DataContext property of its ancestor as long as no one in between explicitly overrides.
If the user control needs data, it should get it from its data source (a viewmodel for the user control). So in this case, the user control can obtain the data it needs from the ListItemsForDisplay property exposed on the SomeViewModel instance. No need to get parent and cast.. much cleaner.

<ContainerType DataSource={Binding SomeViewModel}>
  <YourUserControl>
    <ListBox ItemsSource={Binding ListItemsForDisplay}"/>
...

Answer 5

在此情况下,<代码>UserControl将登上。

<Window>
    <local:MyUserControl DataContext="{Binding}"/>
</Window>

友情链接