[英]Universal App XAML binding not working on UserControl when inside another UserControl
我目前正在使用Windows通用應用程序。 總的來說,我對XAML還是很陌生,但是有一些經驗。
我遇到的問題是圍繞UserControl內部的綁定。 我環顧四周,無法找到特定問題的答案。
我有一個鏈接到ViewModel的XAML頁面,一切正常。 然后在該頁面上,我使用的UserControl基本上只是一個面板,其標題包含一些內容。 在該面板的內容中,我有另一個UserControl,它基本上僅由Label和TextBox組成。
當我將ViewModel的內容綁定到ContentPanel UserControl時,一切工作正常,它將拾取ViewModel上下文並正確綁定。
但是,當我嘗試綁定到ContentPanel包含的LabelledTextbox UserControl時,綁定失敗,因為它只是在ContentPanel上查找ViewModel上的屬性。
請參閱下面的代碼
Page.xaml
<!--Page.xaml-->
<cc:ContentPanel PanelHeading="LEFT FOOT: Measurements" PanelHeadingBackground="{StaticResource OPCare.PanelHeader}">
<StackPanel>
<cc:LabelledTextbox LabelText="Malleoli Width" Text="test" />
<cc:LabelledTextbox LabelText="Met Head Width" />
</StackPanel>
</cc:ContentPanel>
ContentPanel.xaml
<!--ContentPanel UserControl-->
<UserControl
x:Class="OrthoticTabletApp.Controls.ContentPanel"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:OrthoticTabletApp.Controls"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
d:DesignHeight="300"
d:DesignWidth="400"
x:Name="Parent">
<Grid DataContext="{Binding ElementName=Parent}">
<Grid.RowDefinitions>
<RowDefinition Height="50" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid Padding="10" Grid.Column="0" Grid.Row="0" Height="50" Background="{Binding Path=PanelHeadingBackground}">
<TextBlock Height="30" LineHeight="30" Text="{Binding Path=PanelHeading}" />
</Grid>
<Grid Padding="10" Grid.Column="0" Grid.Row="1" Background="White">
<ContentPresenter Content="{Binding Path=PanelBody}" />
</Grid>
</Grid>
</UserControl>
ContentPanel.xaml.cs
[ContentProperty(Name = "PanelBody")]
public sealed partial class ContentPanel : UserControl
{
public static readonly DependencyProperty PanelHeadingProperty = DependencyProperty.Register("PanelHeading", typeof(string), typeof(ContentPanel), new PropertyMetadata(""));
public string PanelHeading
{
get
{
return (string)GetValue(PanelHeadingProperty);
}
set
{
SetValue(PanelHeadingProperty, value);
}
}
public static readonly DependencyProperty PanelBodyProperty = DependencyProperty.Register("PanelBody", typeof(object), typeof(ContentPanel), new PropertyMetadata(null));
public object PanelBody
{
get
{
return (object)GetValue(PanelBodyProperty);
}
set
{
SetValue(PanelBodyProperty, value);
}
}
public Brush PanelHeadingBackground
{
get { return (Brush)GetValue(PanelHeadingBackgroundProperty); }
set { SetValue(PanelHeadingBackgroundProperty, value); }
}
public static readonly DependencyProperty PanelHeadingBackgroundProperty =
DependencyProperty.Register("PanelHeadingBackground", typeof(Brush), typeof(ContentPanel), new PropertyMetadata(null));
public ContentPanel()
{
this.InitializeComponent();
}
}
LabelledTextbox.xaml
<UserControl
x:Class="OrthoticTabletApp.Controls.LabelledTextbox"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:OrthoticTabletApp.Controls"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
d:DesignHeight="50"
d:DesignWidth="400"
x:Name="Parent">
<Grid DataContext="{Binding ElementName=Parent}">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="300" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid Grid.Column="0" Padding="10">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="15" />
</Grid.ColumnDefinitions>
<TextBlock Grid.Column="0" Text="{Binding Path=LabelText}" />
</Grid>
<Grid Grid.Column="1" Padding="10">
<TextBox Text="{Binding Path=Text}" />
</Grid>
</Grid>
</UserControl>
LabelledTextbox.xaml.cs
public sealed partial class LabelledTextbox : UserControl
{
public string LabelText
{
get { return (string)GetValue(LabelTextProperty); }
set { SetValue(LabelTextProperty, value); }
}
// Using a DependencyProperty as the backing store for LabelText. This enables animation, styling, binding, etc...
public static readonly DependencyProperty LabelTextProperty =
DependencyProperty.Register("LabelText", typeof(string), typeof(LabelledTextbox), new PropertyMetadata(null));
public string Text
{
get { return (string)GetValue(TextProperty); }
set { SetValue(TextProperty, value); }
}
// Using a DependencyProperty as the backing store for Text. This enables animation, styling, binding, etc...
public static readonly DependencyProperty TextProperty =
DependencyProperty.Register("Text", typeof(string), typeof(LabelledTextbox), new PropertyMetadata(null));
public LabelledTextbox()
{
this.InitializeComponent();
}
}
但是,當我嘗試綁定到ContentPanel包含的LabelledTextbox UserControl時,綁定失敗,因為它只是在ContentPanel上查找ViewModel上的屬性。
如果我正確理解了您所做的工作,則ContentPanel
某些屬性綁定到頁面的視圖模型中的數據模型,而LabelledTextbox
屬性綁定到其他視圖模型中的數據模型?
如果是這樣,可以為ContentPanel
內部的StackPanel
LabelledTextbox
指定DataContext
,例如:
<cc:ContentPanel PanelHeading="{x:Bind Heading}" PanelHeadingBackground="Azure">
<StackPanel>
<StackPanel.DataContext>
<local:LabelledTextboxViewModel x:Name="VM" />
</StackPanel.DataContext>
<cc:LabelledTextbox LabelText="{x:Bind VM.Lable1}" Text="test" />
<cc:LabelledTextbox LabelText="{x:Bind VM.Lable2}" />
</StackPanel>
</local:ContentPanel>
在頁面的視圖模型中,可以為ContentPanel
創建數據模型並初始化數據,例如:
public BlankPage3ViewModel()
{
Heading = "LEFT FOOT: Measurements";
}
public string Heading { get; set; }
在LabelledTextboxViewModel中,您可以像這樣編寫示例:
public class LabelledTextboxViewModel
{
public LabelledTextboxViewModel()
{
Lable1 = "Malleoli Width";
Lable2 = "Met Head Width";
}
public string Lable1 { get; set; }
public string Lable2 { get; set; }
}
通常,當我們按照MVVM模式開發項目時, 不應將數據模型包含在viewmodel內,我在這里只是為了清晰,輕松地交付 ,關鍵是可以為控件中的不同控件指定不同的DataContext
。同一頁。
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