visual-studio-2010 - 立即窗口， "The expression cannot be evaluated...."

Question

当我尝试在设计时计算立即窗口中的表达式时，出现错误:

The expression cannot be evaluated while in design mode.

如果我编译 ASP.NET 项目并尝试在 Debug模式下运行它，我会收到另一个错误:

The expression cannot be evaluated while in run mode.

为什么我会收到这些错误？我过去曾使用过“立即窗口”，即使在设计模式下它也能正常工作。

Answer 1

假设您在立即窗口中没有缺少 > 运算符，如果您尝试在多项目解决方案甚至是一个项目中的设计时计算表达式，则可能会出现问题网络项目。

根据MSDN :

If you are attempting to evaluate a function in a project that is not the startup project for the solution and you receive an error, try selecting the project in Solution Explorer and attempt the evaluation again.

另外:

You cannot use design time expression evaluation in project types that require starting up an execution environment, including Visual Studio Tools for Office projects, Web projects, Smart Device projects, and SQL projects.