我有同样的问题，期望我把我的主窗口xaml和cs复制到一个新文件，然后把它们复制回原来的地方。在尝试编译WPF应用程序后，我得到了这个错误。

我修复这个错误的方法是重命名命名空间(from egNamespace -> egNamespaceNew)，它再次工作。然后我将名称空间改回原来的名称空间。

给那些在网上找到这个的人。检查窗户。Csproj文件，如果那里有编译。应该有2项

<Page Include="YourFile.xaml">
  <SubType>Designer</SubType>
  <Generator>MSBuild:Compile</Generator>
</Page>

<Compile Include="YourFile.xaml.cs">
  <DependentUpon>YourFile.xaml</DependentUpon>
</Compile>

I had a problem similar to this in WPF. I had copied a usercontrol but had forgotten to rename the public ViewModel property in its.xaml.cs file for it. But still wasn't working. I eventually deleted all of the files inside the obj\debug type of folder for the project (we had this named differently). And rebuilt it. It still wasn't working, and I exited Visual Studio. (Before this I had at one point two instances of Visual Studio I think maybe.) The problem I had was that it was reporting it had this error when I had already fixed it! When I came back into Visual Studio (after deleting the debug stuff in obj), there finally was no error indicator. Then I rebuilt the project and now all was good!

这和我之前做的顺序不一样。它需要被简化。

我尝试了上面所有的建议。如果你太努力而没有成功，那就走更容易的路。创建一个新页面。xaml然后复制新类的代码并删除有问题的类xaml。不要花更多的时间。

在我的情况下，程序实例已经在后台运行。我只是停止运行实例和程序构建成功。

这为我解决了问题。

我已经注释掉了App.xaml文件中的资源

<Application x:Class="MyApp.App" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <Application.Resources>
    <!--<ResourceDictionary>
      <ResourceDictionary.MergedDictionaries>
        <ResourceDictionary
            Source="/PresentationFramework.Aero, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, ProcessorArchitecture=MSIL;component/themes/aero.normalcolor.xaml" />
      </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>-->
  </Application.Resources>
</Application>

将此注释回来以修复构建错误。

<Application x:Class="MyApp.App" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <Application.Resources>
    <ResourceDictionary>
      <ResourceDictionary.MergedDictionaries>
        <ResourceDictionary
            Source="/PresentationFramework.Aero, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, ProcessorArchitecture=MSIL;component/themes/aero.normalcolor.xaml" />
      </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
  </Application.Resources>
</Application>

深入挖掘一下，我发现{Project}\obj\debug中的app.g.cs文件在我留下资源注释时只包含以下内容。

/// <summary>
/// InitializeComponent
/// </summary>
[System.Diagnostics.DebuggerNonUserCodeAttribute()]
public void InitializeComponent() {
    if (_contentLoaded) {
        return;
    }
    _contentLoaded = true;
    System.Uri resourceLocater = new System.Uri("/MyApp;component/app.xaml", System.UriKind.Relative);

    #line 1 "..\..\..\App.xaml"
    System.Windows.Application.LoadComponent(this, resourceLocater);

    #line default
    #line hidden
}