Question

All i have something i have been trying to do for a while and have yet to find a good strategy to do it, i am not sure C# can even support what i am trying to do.

Example imagine a template like this, repeated in manager code overarching cocept function Returns a result consisting of a success flag and error list.

       public Result<Boolean> RemoveLocation(LocationKey key)
        {
           List<Error> errorList = new List<Error>();
           Boolean result = null;
           try{
                result  = locationDAO.RemoveLocation(key);
           }catch(UpdateException ue){
               //Error happened less pass this back to the user!
               errorList = ue.ErrorList;
           }

           return new Result<Boolean>(result, errorList);
        }

Looking to turn it into a template like the below where Do Something is some call (preferably not static) that returns a Boolean. I know i could do this in a stack sense, but i am really looking for a way to do it via object reference.

        public Result<Boolean> RemoveLocation(LocationKey key)
        {
             var magic =  locationDAO.RemoveLocation(key);

             return ProtectedDAOCall(magic);
        }
        public Result<Boolean> CreateLocation(LocationKey key)
        {
             var magic =  locationDAO.CreateLocation(key);

             return ProtectedDAOCall(magic);
        }


        public Result<Boolean> ProtectedDAOCall(Func<..., bool> doSomething)
        {
           List<Error> errorList = new List<Error>();
           Boolean result = null;
           try{
                result  = doSomething();
           }catch(UpdateException ue){
               //Error happened less pass this back to the user!
               errorList = ue.ErrorList;
           }

           return new Result<Boolean>(result, errorList);
        }

If there is any more information you may need let me know.

I am interested to see what someone else can come up with.

---

Marc solution applied to the code above

    public Result<Boolean> CreateLocation(LocationKey key)
    {
        LocationDAO locationDAO = new LocationDAO();
        return WrapMethod(() => locationDAO.CreateLocation(key));
    }


    public Result<Boolean> RemoveLocation(LocationKey key)
    {
        LocationDAO locationDAO = new LocationDAO();
        return WrapMethod(() =>  locationDAO.RemoveLocation(key));
    }


    static Result<T> WrapMethod<T>(Func<Result<T>> func)
    {
        try
        {
            return func();
        }
        catch (UpdateException ue)
        {
            return new Result<T>(default(T), ue.Errors);
        }
    }

Answer 1

Something like:

public Result<Boolean> RemoveLocation(LocationKey key)
{
    return WrapMethod(() => locationDAO.RemoveLocation(key));
}
static Result<T> WrapMethod<T>(Func<T> func) {
    try
    {
        return new Result<T>(func());
    }
    catch (SomeExceptionBase ex)
    {
        return new Result<T>(ex.ErrorList);
    }
    catch (Exception ex)
    {
        return new Result<T>((List<Error>)null);
    }
}

and (minimum shown)

class Result<T>
{
    private Result(bool isError, T value, List<Error> erors) { }
    public Result(T value) : this(false, value, null){ }
    public Result(List<Error> errors) : this(true, default(T), errors) { }
}
class SomeExceptionBase : Exception
{
    public List<Error> ErrorList { get; private set; }
}

(although if I had to do this I’d probably do something more interesting with exceptions that don’t happen to be SomeExceptionBase)