无法创建“”的实例;[用户控制]”;设计器中出现错误
本文关键字:错误 用户 创建 实例 控制 | 更新日期: 2023-09-27 18:29:50
我已经创建了以下用户控件。当我将它添加到xaml窗口时,我得到错误"无法创建"ucAppItem"的实例。我从工具栏将用户控件拖到窗口上。
用户控件的XAML如下:
<UserControl x:Class="Demos.ucAppItem"
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"
mc:Ignorable="d" Width="852" Height="215">
<Grid>
<Label Name="lblTitle" Content="Title" HorizontalAlignment="Left" Margin="233,10,0,0" VerticalAlignment="Top" FontSize="22" FontFamily="Arial"/>
<Image Width="40" Height="40" VerticalAlignment="Center" HorizontalAlignment="Right" Margin="0,0,80,0">
<Image.Style>
<Style TargetType="{x:Type Image}">
<Setter Property="Source" Value="pack://siteoforigin:,,,/arrow2.png"/>
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Source" Value="pack://siteoforigin:,,,/arrow1.png"/>
</Trigger>
</Style.Triggers>
</Style>
</Image.Style>
</Image>
<Label x:Name="lblRun" Content="Run" HorizontalAlignment="Right" Margin="0,88,35,0" VerticalAlignment="Top" Foreground="#FF2EAADC" FontSize="20">
<Label.Style>
<Style TargetType="{x:Type Label}">
<Setter Property="Foreground" Value="#FF2EAADC"/>
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Foreground" Value="#006d9e"/>
</Trigger>
</Style.Triggers>
</Style>
</Label.Style>
</Label>
</Grid>
</UserControl>
窗口的XAML如下:
<Window
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:Demos" x:Class="Demos.Window1"
Title="Window1" Height="487" Width="854">
<Grid>
<local:ucAppItem/>
</Grid>
</Window>
提前感谢您的帮助!
@Anatooil Nikolaev-感谢您的帮助!你在标签上的指针解决了我的问题,你对图像的看法是正确的。我会把你的回答标记为答案。问题出在消息来源身上。
我的标签现在被定义为:
<Label x:Name="lblRun" Content="Run" HorizontalAlignment="Right" Margin="0,88,35,0" VerticalAlignment="Top" FontSize="20">
<Label.Style>
<Style TargetType="{x:Type Label}">
<Setter Property="Foreground" Value="#FF2EAADC"/>
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Foreground" Value="#006d9e"/>
</Trigger>
</Style.Triggers>
</Style>
</Label.Style>
</Label>
我的图像现在被定义为:
<Image>
<Image.Style>
<Style TargetType="{x:Type Image}">
<Setter Property="Source" Value="{StaticResource arrow2}"/>
<Setter Property="Height" Value="40"/>
<Setter Property="Width" Value="40"/>
<Setter Property="VerticalAlignment" Value="Center"/>
<Setter Property="Margin" Value="0,0,80,0"/>
<Setter Property="HorizontalAlignment" Value="Right"/>
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Source" Value="{StaticResource arrow1}"/>
</Trigger>
</Style.Triggers>
</Style>
</Image.Style>
</Image>
我有资源(在App.xaml文件中设置),设置如下:
<Application x:Class="demos.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
StartupUri="MainWindow.xaml">
<Application.Resources>
<BitmapImage x:Key="arrow1" UriSource="arrow1.png" />
<BitmapImage x:Key="arrow2" UriSource="arrow2.png" />
</Application.Resources>
</Application>
首先,不需要pack://siteoforigin:,,,/arrow2.png
,而是需要编写实际的URI
,并确保该文件作为资源存在于项目中,如下所示(MSDN
):
pack://application:,,,/arrow1.png
其次,标签lblRun
的触发器样式将不起作用,因为您在本地设置了此Foreground
值,在WPF中有一个值优先级列表(MSDN
),即本地值的优先级高于触发器样式:
<Label x:Name="lblRun" Foreground="#FF2EAADC" FontSize="20" ... />
尝试删除Foreground
本地值并使用Style
setter:
<Label x:Name="lblRun" Content="Run" HorizontalAlignment="Right" Margin="0,88,35,0" VerticalAlignment="Top" FontSize="20">
<Label.Style>
<Style TargetType="{x:Type Label}">
<Setter Property="Foreground" Value="#FF2EAADC"/>
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Foreground" Value="#006d9e"/>
</Trigger>
</Style.Triggers>
</Style>
</Label.Style>
</Label>