C# IDisposable object for entire class

Question

The project that I'm working on at the moment uses an IDisposable object in every method in a class. It has started getting tedious re-typing the using block at the start of every method, and was wondering if there was a way to specify a disposable variable for use in every method of the class?

public static class ResourceItemRepository
{
    public static ResourceItem GetById(int id)
    {
        using (var db = DataContextFactory.Create<TestDataContext>())
        {
            // Code goes here...
        }
    }
    public static List<ResourceItem> GetInCateogry(int catId)
    {
        using (var db = DataContextFactory.Create<TestDataContext>())
        {
            // Code goes here...
        }
    }
    public static ResourceItem.Type GetType(int id)
    {
        using (var db = DataContextFactory.Create<TestDataContext>())
        {
            // Code goes here...
        }
    }
}

Answer 1

No, there's nothing particularly geared towards this. You could write:

public static ResourceItem GetById(int id)
{
    WithDataContext(db =>
    {
        // Code goes here...
    });
}

// Other methods here, all using WithDataContext

// Now the only method with a using statement:
private static T WithDataContext<T>(Func<TestDataContext, T> function)
{
    using (var db = DataContextFactory.Create<TestDataContext>())
    {
        return function(db);
    }
}

I'm not sure that it would be particularly beneficial though.

(Note that I've had to change it from Action<TestDataContext> in my original version to Func<TestDataContext, T> as you want to be able to return values from your methods.)

Answer 2

private delegate void ContextAction(TestDataContext context);

private static void PerformAction(ContextAction contextAction)
{
        using (var db = DataContextFactory.Create<TestDataContext>()) 
        { 
            contextAction(db);
        } 
}

Answer 3

Frankly, i'd keep the verbose code, but using a snippet instead of typing it all each time. Either create your own snippet with a special tool or use text-replacement tools like Texter

Answer 4

Maybe a simple refactoring is the best that you can do without resorting to something like PostSharp:

public static class ResourceItemRepository {
  public static ResourceItem GetById(int id) {
    using (var db = CreateDataContext()) {
      // Code goes here... 
    }
  }
  public static List<ResourceItem> GetInCateogry(int catId) {
    using (var db = CreateDataContext()) {
      // Code goes here... 
    }
  }
  public static ResourceItem.Type GetType(int id) {
    using (var db = CreateDataContext()) {
      // Code goes here... 
    }
  }
  private static TestDataContext CreateDataContext() {
    return DataContextFactory.Create<TestDataContext>();
  }
}