Will this C# code work in thread-safe mode?

Question

I need to be able to get the Project by ID and safely change the properties of it. I am not the specialist in multi-threading. So, please, help me with this.

public static class Application
{
    private static ConcurrentDictionary<string, Project> projects = new ConcurrentDictionary<string, Project>();

    private static readonly object locker = new object();

    public static Project GetProjectByGuid(string guid)
    {
        if (guid == null) return null;

        lock (locker)
        {
            return projects.GetValueOrDefault(guid, null);
        }
    }

    public static void AddOrUpdateProject(Project project)
    {
        Project dbProject;

        lock (locker)
        {
            dbProject = GetProjectByGuid(project.Guid);
            if (dbProject == null)
            {
                projects[project.Guid] = project;
            }
        }

        if (dbProject != null)
        {
            lock (dbProject.locker)
            {
                dbProject.Name = project.Name;
                dbProject.Users = project.Users;
            }
        }
    }
}

The use of a ConcurrentDictionary means you shouldn't need to add lock objects to your methods when interacting with the dictionary — oppassum, Feb 01 '18 at 19:07
If `Project` is not thread safe then no amount of locking around the dictionary it's stored in will make it thread safe. If two threads have a reference to the same `Project` then it doesn't matter how they got it. You would either want to ensure that multiple threads don't both interact with the same `Project` instance or make `Project` thread safe. — Scott Hannen, Feb 01 '18 at 19:14

score 0 · Accepted Answer · answered Feb 01 '18 at 19:57

0

Since the Project object is not thread safe, the answer to your question is no, you will not be able to make this thread safe.

answered Feb 01 '18 at 19:57

Lajos Arpad

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Will this C# code work in thread-safe mode?

1 Answers1