c# - 确定 EnvDTE.Project 是否可用

Question

我必须经历一个包含不可用项目的大型解决方案。这些不可用的项目不可用，因为它们的路径不再存在。如果这个解决方案要保留这些不可用的引用，是否有一种方法可以确定我正在循环的每个项目是否可用？

下面是一个循环，其目标是确定是否保存了当前解决方案中的每个 ProjectItem。但是，由于某些项目不可用，我不断收到空引用。

bool isDirty = false;
foreach (Project proj in sln.Projects) //sln is my current solution
{
    if (proj == null) //hoping that might do the trick
        continue;
    foreach (ProjectItem pi in proj.ProjectItems)
    {
        if (pi == null) //hoping that might do the trick
            continue;
        if (!pi.Saved)
        {
            isDirty = true;
            break;
        }
    }
}

Answer 1

您可以用一个简单的 LINQ 重写它操作:

//import the LINQ extensions
using System.Linq;
// some code here;
bool isDirty = sln.Projects.Any(pr => pr.ProjectItems != null && !pr.Saved);

根据 MSDN， _Solution.Projects 属性是 Projects 输入，这是一个 IEnumerable没有泛型，所以你应该使用 OfType<TResult> 扩展方法，像这样:

bool isDirty = sln.Projects.OfType<Project>().Any(pr => pr.ProjectItems != null && !pr.Saved);

来自 MSDN:

This method is one of the few standard query operator methods that can be applied to a collection that has a non-parameterized type, such as an ArrayList. This is because OfType<TResult> extends the type IEnumerable. OfType<TResult> cannot only be applied to collections that are based on the parameterized IEnumerable<T> type, but collections that are based on the non-parameterized IEnumerable type also.