像许多其他人一样，我看到了这个编译错误。我是一名多年的开发人员，在多年后回到 WPF。

我有一个针对单个项目的解决方案net6.0-windows（切换到net5.0-windows下面进行测验）。该项目是在 VS 2022 Pro 中创建的。我没有;assembly=在clr-namespace:宣告中指定。在广泛阅读 SO 后，我相信这两种情况是导致此错误的最常见原因。

项目

<Project Sdk="Microsoft.NET.Sdk">    
  <PropertyGroup>
    <OutputType>WinExe</OutputType>
    <TargetFramework>net5.0-windows</TargetFramework>
    <Nullable>annotations</Nullable>
    <UseWPF>true</UseWPF>
    <AssemblyName>NTS$(MSBuildProjectName)Boards</AssemblyName>
  </PropertyGroup>    
</Project>

用户控制元件

<UserControl x:Class="EndGrain.View.AssemblyPartControl"
             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:vw="clr-namespace:EndGrain.View"
             xmlns:vm="clr-namespace:EndGrain.ViewModel"
             mc:Ignorable="d" 
             >
...
    <Grid Background="{StaticResource BackgroundBrush}">
...
    </Grid>
</UserControl>

UserControl 代码隐藏

using System.Windows.Controls;

namespace EndGrain.View
{
    /// <summary>
    /// Interaction logic for AssemblyPartControl.xaml
    /// </summary>
    public partial class AssemblyPartControl : UserControl
    {
        public AssemblyPartControl()
        {
            InitializeComponent();
        }
    }
}

看法

<Window x:Class="EndGrain.View.AssemblyPartSandboxView"
        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:vw="clr-namespace:EndGrain.View"
        mc:Ignorable="d"
        Title="AssemblyPartSandboxView" Height="100" Width="200">
    <Grid>
        <vw:AssemblyPartControl Width="100" Height="30" />
    </Grid>
</Window>

我试过的

从 Visual Studio Professional 2022 17.0.2 开始

- Built the project without the UserControl. Builds fine.
- Typed in the <vw:AssemblyPartControl /> element. Built the project. Error list shows the error.
- Changing the target framework back to net5.0-windows (from net6.0-windows) does not help.

用Visual Studio 2019 Enterprise 16.11.7打开net5项目

- Rebuilt the project. Error shows.
- Commented out the UserControl. Rebuilt. Builds fine.
- Uncommented the UserControl. Rebuilt. Error shows.

使用 Blend for Visual Studio Enterprise 2019 16.11.7 打开

- Dragged the UserControl to the design surface. Blend added the element with the vw namespace.
- Built the project, and the Error List shows the error.

;assembly=NTSEndGrainBoards在命名空间定义中添加，因为我已经覆写了默认程序集名称。没有效果。

希望一双敏锐的眼睛能看到我犯下的愚蠢错误；不可能这幺难。预先感谢您的帮助。

uj5u.com热心网友回复：

当我完成我的问题时，我决定尝试洗掉非标准程序集名称。这就是诀窍。希望这对其他人有帮助，再次感谢您的关注。

修订项目

<Project Sdk="Microsoft.NET.Sdk">    
  <PropertyGroup>
    <OutputType>WinExe</OutputType>
    <TargetFramework>net5.0-windows</TargetFramework>
    <Nullable>annotations</Nullable>
    <UseWPF>true</UseWPF>
  </PropertyGroup>    
</Project>