.NET 4.5 is an in-place replacement for .NET 4.0, When .NET 4.5 is installed it effectively replaces .NET 4.0 on the machine. .NET 4.0 gets overwritten by a new version of .NET 4.5 which - according to Microsoft - is supposed to be 100% backwards compatible. 我们简单的理解就是,4.5本质上还是4.0,属于递增式的更新,所以对IIS 来说看到的只有4.0而已,看看如下的4.5 DLL库中的版本号就知道了 |