从 .NET 4.5 升级到 4.6.2 Designer 后停止工作，为什么？答案

【问题标题】：After upgrading from .NET 4.5 to 4.6.2 Designer stopped working why?从 .NET 4.5 升级到 4.6.2 Designer 后停止工作，为什么？
【发布时间】：2022-08-08 02:58:13
【问题描述】：

Microsoft Visual Studio Community 2019 版本 16.11.8（在本文发布时是最新的）

它是最初使用 .NET 4.5 Framework 创建的 CLR 项目。我不得不将它升级到 4.6.2 但是我发现了一个可能的错误。如果您在System::Windows::Forms::Form 中添加了System::Windows::Forms::Timer 或System::ComponentModel::IContainer，那么升级后Designer 将停止工作。

这是由Visual Studio 生成的虚拟项目，它显示了重现错误所需的内容。

#pragma once

namespace Net45Test {

    using namespace System;
    using namespace System::ComponentModel;
    using namespace System::Collections;
    using namespace System::Windows::Forms;
    using namespace System::Data;
    using namespace System::Drawing;

    /// <summary>
    /// Summary for MyForm
    /// </summary>
    public ref class MyForm : public System::Windows::Forms::Form
    {
    public:
        MyForm(void)
        {
            InitializeComponent();
            //
            //TODO: Add the constructor code here
            //
        }

    protected:
        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        ~MyForm()
        {
            if (components)
            {
                delete components;
            }
        }
    private: System::Windows::Forms::Timer^ timer1;
    protected:
    private: System::ComponentModel::IContainer^ components;

    private:
        /// <summary>
        /// Required designer variable.
        /// </summary>


#pragma region Windows Form Designer generated code
        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        void InitializeComponent(void)
        {
            this->components = (gcnew System::ComponentModel::Container());
            this->timer1 = (gcnew System::Windows::Forms::Timer(this->components));
            this->SuspendLayout();
            // 
            // MyForm
            // 
            this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
            this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
            this->ClientSize = System::Drawing::Size(284, 261);
            this->Name = L\"MyForm\";
            this->Text = L\"MyForm\";
            this->ResumeLayout(false);

        }
#pragma endregion
    };
}

Designer 错误：

C++ CodeDOM parser error: Line: 54, Column: 21 --- Unknown type \'\'. Please make sure that the assembly that contains this type is referenced. If this type is a part of your development project, make sure that the project has been successfully built.
at Microsoft.VisualC.CppCodeParser.OnMethodPopulateStatements(Object sender, EventArgs e)
at System.CodeDom.CodeMemberMethod.get_Statements()
at System.ComponentModel.Design.Serialization.TypeCodeDomSerializer.Deserialize(IDesignerSerializationManager manager, CodeTypeDeclaration declaration)
at System.ComponentModel.Design.Serialization.CodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager manager)
at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager serializationManager)
--- End of stack trace from previous location where exception was thrown ---
at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager serializationManager)
at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomDesignerLoader.DeferredLoadHandler.Microsoft.VisualStudio.TextManager.Interop.IVsTextBufferDataEvents.OnLoadCompleted(Int32 fReload)

我是否正确更改了目标框架版本，如下图所示，我应该做其他事情吗？

所以假设我做对了，这里发生了什么？ Visual Studio 错误还是别的什么？

标签： .net visual-studio c++-cli clr

【解决方案1】：

Microsoft 还没有修复，还好我找到了修复的方法，你需要在你的电脑上启用隐藏文件夹并进入你的项目目录然后删除 .vs 隐藏文件夹，这样下次你加载您的项目，Designer 应该可以工作。

【讨论】：