【发布时间】：2013-02-15 08:08:11
【问题描述】：
我在一个简单的 WinRT 演示项目中有两个非常简单的 UserControl。没有 Viewmodel——主要是用于布局探索的彩色框。我创建的第一个 UserControl 工作正常。第二个非常相似，不会绑定到任何属性——它显示为空白。
第一个 UserControl 如下所示：
<UserControl
x:Class="Demo.SmallStartTile"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:Demo"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
x:Name="SmallStartTileUC"
d:DesignHeight="300"
d:DesignWidth="400">
<Grid x:Name="SmallTileGrid"
Margin="0,0,8,8"
Background="{Binding Background, ElementName=SmallStartTileUC}"
>
<Rectangle
Stroke="{Binding BorderBrush, ElementName=SmallStartTileUC}"
Grid.RowSpan="2"
/>
<TextBlock x:Name="SmallTileTitle"
Text="{Binding TileText, ElementName=SmallStartTileUC}"
Style="{StaticResource SmallTileHeader}"/>
<Path x:Name="IconPath"
Style="{StaticResource SmallTileIcon}"
Data="{Binding TileIconPathData, ElementName=SmallStartTileUC}" />
</Grid>
</UserControl>
namespace Demo
{
public sealed partial class SmallStartTile : UserControl
{
public static DependencyProperty TileTextProperty = DependencyProperty.Register("TileText", typeof(string), typeof(SmallStartTile), new PropertyMetadata("tile content"));
public string TileText
{
get { return (string)GetValue(TileTextProperty); }
set { SetValue(TileTextProperty, value); }
}
public static DependencyProperty TileIconPathDataProperty = DependencyProperty.Register("TileIconPathData", typeof(string), typeof(SmallStartTile), new PropertyMetadata("F0"));
public string TileIconPathData
{
get { return (string)GetValue(TileIconPathDataProperty); }
set { SetValue(TileIconPathDataProperty, value); }
}
public SmallStartTile()
{
this.InitializeComponent();
}
}
}
第二个，就像第一个一样，通过单击添加新项目并在 Blend 中选择 UserControl：
<UserControl
x:Class="Demo.SmallMediaTile"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:Demo"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
x:Name="SmallMediaTileUC"
d:DesignHeight="300"
d:DesignWidth="400">
<Grid
Margin="0,0,8,8"
Background="{Binding Background, ElementName=SmallMediaTileUC}"
>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Rectangle
Stroke="{Binding BorderBrush, ElementName=SmallMediaTileUC}"
Grid.RowSpan="2"
/>
<Viewbox
Margin="30"
Child="{Binding Content, ElementName=SmallMediaTileUC}">
</Viewbox>
<TextBlock
Grid.Row="1"
Text="{Binding SourceText, ElementName=SmallMediaTileUC}"
Style="{StaticResource SmallMusicTileHeader}"/>
</Grid>
</UserControl>
namespace Demo
{
public sealed partial class SmallMediaTile : UserControl
{
public static DependencyProperty SourceTextProperty = DependencyProperty.Register("SourceText", typeof(string), typeof(SmallMediaTile), new PropertyMetadata("source"));
public string SourceText
{
get { return (string)GetValue(SourceTextProperty); }
set { SetValue(SourceTextProperty, value); }
}
public SmallMediaTile()
{
this.InitializeComponent();
}
}
}
我在主页中这样使用 UserControl：
<local:SmallMediaTile x:Name="Source1Tile"
Grid.Column="0" Grid.Row="0"
SourceText="Radio"
Background="Blue"
BorderBrush="Red">
<local:SmallMediaTile.Content>
<Canvas x:Name="radio_icon" Height="68" Width="34">
<Path Data="F1M299.6182,396.2988C299.6182,389.7208,297.0722,383.5548,292.4572,378.8398L288.6162,382.6758C292.2022,386.3718,294.1842,391.1778,294.1842,396.2988C294.1842,401.4238,292.2022,406.2368,288.6162,409.9328L292.4572,413.7738C297.0722,409.0538,299.6182,402.8808,299.6182,396.2988" Fill="White" Height="34.934" Canvas.Left="0" Stretch="Fill" Canvas.Top="16.501" Width="11.002"/>
<Path Data="F1M311.1738,396.2988C311.1738,386.6278,307.4348,377.5528,300.6788,370.6208L296.8258,374.4618C302.5658,380.3698,305.7398,388.0798,305.7398,396.2988C305.7398,404.5218,302.5658,412.2298,296.8258,418.1428L300.6788,421.9898C307.4348,415.0498,311.1738,405.9718,311.1738,396.2988" Fill="White" Height="51.369" Canvas.Left="8.21" Stretch="Fill" Canvas.Top="8.282" Width="14.348"/>
<Path Data="F1M322.7578,396.2988C322.7578,383.5298,317.8508,371.5348,308.9638,362.3388L305.1168,366.1748C312.9758,374.3538,317.3338,384.9778,317.3338,396.2988C317.3338,407.6208,312.9758,418.2488,305.1168,426.4268L308.9638,430.2748C317.8508,421.0698,322.7578,409.0798,322.7578,396.2988" Fill="White" Height="67.936" Canvas.Left="16.501" Stretch="Fill" Canvas.Top="0" Width="17.641"/>
</Canvas>
</local:SmallMediaTile.Content>
</local:SmallMediaTile>
第一个拾取所有属性并按预期显示，但第二个仅拾取 Viewbox 内容。我已经查看了 SO 并一直在谷歌搜索，但无法弄清楚问题所在。对不起，如果这是冗长的。
【问题讨论】：
-
我看不到任何明显的东西，但您能在 Visual Studio 的调试输出窗口中检查绑定错误吗？
-
什么具体不起作用？当我尝试将 Viewbox 的 Child 绑定到 UserControl 的不存在的 Content 属性时，我可以看到控件崩溃，但如果我删除它 - 它似乎工作正常。
-
我想我的队友已经找到了答案。问题是视图框。在页面 XAML 中设置 Viewbox 内容会覆盖 UserControl 的内容。所以真正的问题是：如何将 Canvas 内容插入到 UserControl 中？我会结束这个问题并问那个问题。
-
编辑问题以在主页中显示 UserControl，这似乎是问题所在。
-
另一个答案是 - 这取决于。这取决于你想如何处理这个问题。您可以使用模板化的 ContentControl 而不是 UserControl 并修改其模板以添加 TextBlock 等。您还可以继续使用 UserControl 并添加一些其他依赖属性，这些属性将绑定到您的 Viewbox 的内容 (
Child)。
标签： xaml windows-runtime winrt-xaml