VS2017中C++ WinForms设计视图无法显示求助（VS2010迁移项目）

Hey there! I totally get how frustrating this can be when you're still getting up to speed with C++ and dealing with Visual Studio migrations—let's walk through the fixes step by step to get your old WinForms design views back up and running.

Step 1: Correct the Project File (.vcxproj) Settings #

Most often, the migration from VS2010 to 2017 messes up the item type configuration for old WinForms files. Here's how to fix it:

• Right-click your project in the Solution Explorer and select Unload Project.
• Right-click the unloaded project and choose Edit [YourProjectName].vcxproj.
• In the XML file, find the entry for your old WinForms header file (e.g., OldForm.h). It’ll probably look like this:

  <ClInclude Include="OldForm.h" />
  

• Replace it with the format used by your working new WinForms items—add the FileType and CustomTool properties:

  <ClInclude Include="OldForm.h">
    <FileType>Designer</FileType>
    <CustomTool>MFCClassGenerator</CustomTool>
  </ClInclude>
  

• Save the .vcxproj file, then right-click the project and select Reload Project.

Step 2: Verify and Run the Custom Tool #

If the icon still shows as "H", check the file’s properties to ensure the custom tool is set correctly:

• Right-click the problematic header file and select Properties.
• Navigate to Configuration Properties → General and confirm the Item Type is set to C/C++ Header (this is normal for WinForms headers).
• Look for the Custom Tool field (location varies slightly by VS version) and set it to MFCClassGenerator.
• Click Apply, then right-click the file again and select Run Custom Tool. This triggers VS to regenerate the design-time metadata, and the icon should switch to the WinForms design view icon.

Step 3: Check for Missing .designer.h Files #

WinForms in C++ relies on a paired .designer.h file that holds auto-generated design code. If this file is missing or mislinked:

• Make sure OldForm.designer.h exists in your project directory. If it’s gone, restore it from a backup if you have one.
• Open your main header file (e.g., OldForm.h) and confirm it includes the designer file at the bottom:

  #include "OldForm.designer.h"
  

• If the designer file exists but isn’t showing in the Solution Explorer, right-click the project, select Add → Existing Item, and add it back.

Step 4: Reset Visual Studio’s User Data (Last Resort) #

If none of the above work, VS’s cached user data might be corrupted:

• Close all instances of Visual Studio.
• Open an Administrator Command Prompt and run this command:

  devenv /resetuserdata
  

• Restart VS, open your project, and check if the design view loads properly.

Quick Check #

Double-check your project’s CLR support: Right-click the project → Properties → Configuration Properties → General, and ensure Common Language Runtime Support is set to Common Language Runtime Support (/clr). Migrations sometimes disable this, which breaks WinForms functionality.

内容的提问来源于stack exchange，提问作者Satish Kumar