“无法评估表达式”和异步 CTP
前段时间我安装了 Visual Studio Async CTP
，今天我安装了 ASP.NET MVC 3（不是 RC）。
我开始在调试模式下收到“无法评估表达式”。
所以我卸载了 Async CTP、ASP.NET MVC 3 和所有相关更新，但没有任何结果。 有好心人帮我解答一下吗？
消息示例：
Unable to evaluate expression term 'struct'
Some time ago I have installed the Visual Studio Async CTP
And today I have installed ASP.NET MVC 3 (not RC).
I start receiving "Unable to evaluate expression" in debug mode.
So I have uninstalled Async CTP, ASP.NET MVC 3 and all related updates but with no results.
Would be anybody so kind as to help me figure out?
Example message:
Unable to evaluate expression term 'struct'
如果你对这篇内容有疑问，欢迎到本站社区发帖提问 参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。
绑定邮箱获取回复消息
由于您还没有绑定你的真实邮箱，如果其他用户或者作者回复了您的评论，将不能在第一时间通知您！
发布评论
评论（4）
好的，这是我的经验。我终于让它工作了...并且不需要完全卸载 VS 2010。
首先，我不确定我是否安装了 ASP NET MVC 3 RC。我已经有了 ASP NET MVC 3 RTM，然后安装了 Async CTP。我开始遇到描述的问题，然后卸载 Async CTP 和 MVC 3，没有帮助...我后来意识到我做得还不够：
在控制面板中：
然后在控制面板 -> 卸载程序中单击“查看已安装的更新”：
现在安装 ASP NET MVC 3 RTM，它应该可以工作。
OK, here is my experience. I finally got it working... and no full uninstall of VS 2010 was required.
First of all, I am not sure if I had installed ASP NET MVC 3 RC or not. I already had ASP NET MVC 3 RTM and then installed Async CTP. I started getting issues described then uninstalled Async CTP and MVC 3, did not help... I later realised I had not done enough:
In control panel:
Then click on "View installed updates" in Control Panel->Uninstall A Program:
Now install ASP NET MVC 3 RTM and it should work.
显然，当 MVC 3 RC 和 .NET Framework Async CTP 安装在同一台计算机上时，就会出现此问题。
您需要卸载 MVC 3 RC，但由于它还附带 ASP.NET 网页、NuGet 和 Visual Studio 更新，因此必须将它们一起删除。
要继续，请使用管理员权限打开 Visual Studio 命令提示符* 并运行以下所有命令：
wmic Product where name="Microsoft ASP.NET MVC 3 - Visual Studio 2010 Tools" call uninstall
wmic Product where name="Microsoft ASP.NET MVC 3 - VWD Express 2010 工具”调用卸载
wmic 产品，其中 name="Microsoft ASP.NET 网页”调用卸载
wmic 产品，其中 name="Microsoft ASP.NET 网页 - Visual Studio 2010 工具”调用卸载
wmic 产品，其中 name= “Microsoft ASP.NET 网页 - VWD Express 2010 工具”调用卸载
wmic 产品，其中 name="NuGet" 调用卸载
msiexec /package {BC0464FA-A0BA-3E38-85BF-DC5B3A401F48} /uninstall {3069D446-63C5-38F4-9D28- 41858024419C}
msiexec /package {85076DFF-7A17-3566-9CC0-488E6E6D4494} /uninstall {3069D446-63C5-38F4-9D28-41858024419C}
如果问题仍然存在，请同时卸载 .NET Framework Async CTP。
Apparently this problem arises when both MVC 3 RC and .NET Framework Async CTP are installed on the same machine.
You need to uninstall MVC 3 RC but since it also comes with ASP.NET Web Pages, NuGet and a Visual Studio update those have to be removed along with it.
To proceed open a Visual Studio command prompt* with Administrator privilege and run all of the following commands:
wmic product where name="Microsoft ASP.NET MVC 3 - Visual Studio 2010 Tools" call uninstall
wmic product where name="Microsoft ASP.NET MVC 3 - VWD Express 2010 Tools" call uninstall
wmic product where name="Microsoft ASP.NET Web Pages" call uninstall
wmic product where name="Microsoft ASP.NET Web Pages - Visual Studio 2010 Tools" call uninstall
wmic product where name="Microsoft ASP.NET Web Pages - VWD Express 2010 Tools" call uninstall
wmic product where name="NuGet" call uninstall
msiexec /package {BC0464FA-A0BA-3E38-85BF-DC5B3A401F48} /uninstall {3069D446-63C5-38F4-9D28-41858024419C}
msiexec /package {85076DFF-7A17-3566-9CC0-488E6E6D4494} /uninstall {3069D446-63C5-38F4-9D28-41858024419C}
If the problem still persists however uninstall .NET Framework Async CTP as well.
当尝试在调试器中加载语言表达式计算器时出现相当严重的错误或者表达式计算器本身存在设置问题时，通常会出现此错误消息。我接下来要尝试的是修复 Visual Studio 安装。这几乎肯定会消除这个错误。
This error message usually arises when there is a fairly critical error trying to load the language expression evaluator in the debugger or if the expression evaluator itself has a setup issue. The very next thing I would try is to repair the Visual Studio installation. That will almost certainly clear up this error.
完全卸载所有 Visual Studio 组件对我有帮助。
Full uninstall all visual studio components helped me.