我目前正在创建一个应用程序来测试 WPF 的灵活性。我有一些用户控件,当涉及到其 ViewModel 时,它们的目的是非常透明的。我所说的透明是指用户控件可以使用任何类型的 ViewModel,前提是 ViewModel 具有绑定(bind)到该用户控件内的控件所需的所有属性。我通过将 ViewModel 分配为特定用户控件的数据上下文来实现此目的。
当只有两个用户控件时(一个可以访问 ViewModelLocator,一个需要前者的数据上下文声明),此方法有效。当用户控件达到 3 层或更多时,我不知道该怎么办。有没有办法在驻留在有权访问 ViewModelLocator 的用户控件中的用户控件中设置用户控件的数据上下文?
下面是一些可以澄清我的问题的代码。
此代码是父用户控件。它旨在用于利用 MAF 的应用程序。我使用非静态 ViewModelLocator 来确保每个插件实例使用不同的 ViewModelLocator 实例,并且因为该插件没有自己的 app.xaml (因此没有全局资源)。正如您所看到的,我将一个来自单独程序集的用户控件放置在网格中,然后声明其数据上下文,以便所述用户控件能够与父用户控件的 ViewModelLocator 进行交互。
<UserControl x:Class="TestApp.Inventory.Common.Views.MaterialsNewView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:vm="clr-namespace:TestApp.Inventory.Common.ViewModel"
xmlns:views="clr-namespace:TestApp.Inventory.Common.Views"
xmlns:viewsSupp="clr-namespace:TestApp.Supplier.Common.Views;assembly=TestApp.Supplier.Common"
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" Height="607" Width="616" Loaded="UserControl_Loaded">
<UserControl.Resources>
<vm:ViewModelLocator x:Key="Locator" />
</UserControl.Resources>
<UserControl.DataContext>
<Binding Path="MaterialsNewView" Source="{StaticResource Locator}" />
</UserControl.DataContext>
<Grid>
<views:SupplierView x:Name="supplierView" Margin="145,306,0,0" HorizontalAlignment="Left" Width="328" Height="258" VerticalAlignment="Top" DataContext="{Binding Source={StaticResource Locator}, Path=SupplierView}" />
</Grid>
</UserControl>
然后我就有了子用户控件的代码。就像我之前所说的那样,子用户控件的目的是在 ViewModel 方面是透明的。这就是为什么每次都应该在父用户控件中声明数据上下文。
<UserControl x:Class="TestApp.Supplier.Common.Views.SupplierView"
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:ignore="http://www.ignore.com"
mc:Ignorable="d ignore" Height="289" Width="352"
xmlns:my="clr-namespace:TestApp.Lookup.Common.Views;assembly=TestApp.Lookup.Common">
<Grid>
<my:MaterialTypeListView Height="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=Grid, AncestorLevel=1}, Path=ActualHeight}" HorizontalAlignment="Left" Name="materialTypeListView1" VerticalAlignment="Top" Width="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=Grid, AncestorLevel=1}, Path=ActualWidth}" />
</Grid>
</UserControl>
我的问题是当子用户控件有自己的子用户控件时。我不知道如何从父用户控件声明其数据上下文。目标是无论有多少层用户控件,它们都应该与父用户控件的 ViewModelLocator 交互。
最佳答案
将DependencyProperty
添加到名为MaterialTypeList的UserControlSupplierView。
public partial class SupplierView
{
public List<string> MaterialTypeList
{
get { return (List<string>)GetValue(MaterialTypeListProperty); }
set { SetValue(MaterialTypeListProperty, value);}
}
public static readonly DependencyProperty MaterialTypeListProperty =
DependencyProperty.Register("MaterialTypeList", typeof(string), typeof(SupplierView),
new PropertyMetadata(null));
}
将SupplierView上的UserControl MaterialNewView的绑定(bind)添加到MaterialTypeList
<UserControl x:Class="TestApp.Supplier.Common.Views.SupplierView"
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:ignore="http://www.ignore.com"
mc:Ignorable="d ignore" Height="289" Width="352"
xmlns:my="clr-namespace:TestApp.Lookup.Common.Views;assembly=TestApp.Lookup.Common">
<Grid>
<my:MaterialTypeListView
DataContext="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=UserControl, AncestorLevel=1}, Path=MaterialTypeList}"
Height="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=Grid, AncestorLevel=1}, Path=ActualHeight}" HorizontalAlignment="Left" Name="materialTypeListView1" VerticalAlignment="Top" Width="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=Grid, AncestorLevel=1}, Path=ActualWidth}" />
</Grid>
</UserControl>
将 MaterialTypeListView 上的 UserControl SupplyView 的绑定(bind)添加到 MaterialTypeList。
<UserControl x:Class="TestApp.Inventory.Common.Views.MaterialsNewView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:vm="clr-namespace:TestApp.Inventory.Common.ViewModel"
xmlns:views="clr-namespace:TestApp.Inventory.Common.Views"
xmlns:viewsSupp="clr-namespace:TestApp.Supplier.Common.Views;assembly=TestApp.Supplier.Common"
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" Height="607" Width="616" Loaded="UserControl_Loaded">
<UserControl.Resources>
<vm:ViewModelLocator x:Key="Locator" />
</UserControl.Resources>
<UserControl.DataContext>
<Binding Path="MaterialsNewView" Source="{StaticResource Locator}" />
</UserControl.DataContext>
<Grid>
<views:SupplierView x:Name="supplierView" Margin="145,306,0,0"
MaterialTypeList="{Binding [HERE YOUR LIST OF MATERIALTYPE]}"
HorizontalAlignment="Left" Width="328" Height="258" VerticalAlignment="Top" DataContext="{Binding Source={StaticResource Locator}, Path=SupplierView}" />
</Grid>
</UserControl>
关于c# - 在用户控件内设置用户控件的数据上下文,无论用户控件有多少层,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/16148442/