Determining if a EnvDTE.Project is available

Question

I'm having to go through a big solution that contains unavailable projects. These unavailable projects are unavailable because their paths don't exist anymore. If this solution were to keep these unavailable references, would there be a way to determine if each project I am looping on is available/unavailable?

Below is a loop whose goal is to determine if every ProjectItem within the current solution is saved. But, since certain projects are unavailable, I keep getting null references.

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

You can rewrite this in a simple LINQ operation:

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

According to the MSDN, the _Solution.Projects property is a Projects typed, which is a IEnumerable without generic, so you should use the OfType<TResult> extension method, like this:

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

From 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.