C# Refactoring the same action with different details using design patterns

Question

I try to find the way for refactoring my code but no idea how to do this.

For example, we have several classes

class A {
     string name;
     int year;
}

class B {
      long id;
      string code; 
      DateTime currentTime;
}

class C {
      string lastname;
      DateTime currentDate; 
}

And latter I need to return list of objects of these classes List, List, List and convert them into Object[][].

For every conversion I do the same

private Object[][] converAListToObjectArray(List<A> dataList)
        {
            long countRecords = dataList.Count();
            const int countProperty = 2;
            var arrayRes = new object[countRecords][];

            for (int i = 0; i < countRecords; i++)
            {
                var arrayObjProperty = new object[countProperty];
                arrayObjProperty[0] = dataList[i].Name;
                arrayObjProperty[1] = dataList[i].Year;

                arrayRes[i] = arrayObjProperty;
            }
            return arrayRes;
        }

private Object[][] converBListToObjectArray(List<B> dataList)
        {
            long countRecords = dataList.Count();
            const int countProperty = 3;
            var arrayRes = new object[countRecords][];

            for (int i = 0; i < countRecords; i++)
            {
                var arrayObjProperty = new object[countProperty];
                arrayObjProperty[0] = dataList[i].Id;
                arrayObjProperty[1] = dataList[i].Code;
                arrayObjProperty[2] = dataList[i].CurrentTime; 

                arrayRes[i] = arrayObjProperty;
            }
            return arrayRes;
        }

Is it possible separate this convertion using some design pattern?

its not clear what you are trying to accomplish here.. are you trying to get a generic, convert list to 2d array function? — Sayse, Apr 24 '13 at 20:16
@Sayse I try create unified function which convert list any object to 2d array — Ray, Apr 24 '13 at 20:22
This is just a genuinely weird thing to do, though. What case are you working in where you'll be shuttling around objects in this fashion? Why wouldn't Generics work here? — Reacher Gilt, Apr 24 '13 at 20:30
If this is really just for Excel, and you're using Excel 2007 or later, please read [Office Open XML Formats: Inserting Values into Excel 2007 Cells](http://msdn.microsoft.com/en-us/library/bb508943(v=office.12).aspx) — Reacher Gilt, Apr 24 '13 at 21:03

score 3 · Answer 1 · answered Apr 24 '13 at 20:23

You could write a generic function which uses reflection to get each object's field names and values. You'd need to decide whether it should work for public or private fields. The example below grabs both the public and the private fields:

static object[][] ConvertToObjectArray<T>(IList<T> objects)
{
    var fields = (from fieldInfo in typeof(T).GetFields(
        System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance)
                  orderby fieldInfo.Name
                  select fieldInfo).ToArray();

    object[][] table = new object[objects.Count][];
    for (int i = 0; i < table.Length; i++)
    {
        table[i] = (from fieldInfo in fields
                    select fieldInfo.GetValue(objects[i])).ToArray();
    }
    return table;
}

This is what I was thinking, but I really question what the use case is here. — sidesinger, Apr 24 '13 at 20:42

ed_me · Accepted Answer · 2013-04-24T20:37:45.660

You could use an action and do something like this: -

class Program
{
    // Your new function, (doesn't have to be static; just did it for the demo)
    // If you really really want to return object[][] still,
    // You'll need to pass an index to foo as well
    private static List<IList<object>> convert<T>(IList<T> dataList, Action<IList<object>, T> foo)
    {
        var arrayRes = new List<IList<object>>();

        foreach (var item in dataList)
        {
            var arrayObjProperty = new List<object>();
            foo(arrayObjProperty, item);

            arrayRes.Add(arrayObjProperty);
        }
        return arrayRes;
    }

    // The rest is just calling the function with two examples
    static void Main(string[] args)
    {
        var bar = new List<A>();
        bar.Add(new A() { name = "qux", year = 2013 });

        var objects1 = convert(bar, (a, b) =>
        {
            a.Add(b.name);
            a.Add(b.year);
        });

        var baz = new List<B>();
        baz.Add(new B() { code = "qux", id = 2013 });

        var objects2 = convert(baz, (a, b) =>
        {
            a.Add(b.code);
            a.Add(b.id);
        });
    }
}

You can just copy this into your IDE to have a play and see how it works. Basically, this uses generics and then an action to allow you to do the only part that differs each time in a lambda that is passed to the method.

score 0 · Answer 3 · answered Apr 24 '13 at 20:18

You could simplify and use something like this - e.g. for B...

List<B> list = new List<B> 
{
    new B{ id = 1, code = "", currentTime = DateTime.Now},
    new B{ id = 1, code = "", currentTime = DateTime.Now},
    new B{ id = 1, code = "", currentTime = DateTime.Now},
};

var array = list.Select(x => new object[] { x.id, x.code, x.currentTime }).ToArray();

Reacher Gilt · Answer 4 · 2013-04-24T20:46:36.390

0

Your Object[][] structure is a little unusual to my eye. Did you know there's a Cast method for lists?

You can do the following:

List<A> foo = new List<A> ();

// initialize foo here
var bar = foo.Cast<Object>().ToArray();

Which will get you a an array of objects with your field names intact. If you absolutely need to have the fields as array elements (why do you want this) you could add a ToObject method to each of your classes:

class A
{
    public string name;
    public int year;
    public Object[] ToObject()
    {
        return new Object[] {name, year};
    }
}


    List<A> foo = new List<A>
    {
        new A{name="reacher",year=2013},
        new A{name="Ray",year=2013}
    }; 
    var bux = foo.Select(a => a.ToObject()).ToArray() ;

edited Apr 24 '13 at 20:46

answered Apr 24 '13 at 20:28

Reacher Gilt

1,813
12
26

I need to fill data range in Excel – Ray Apr 24 '13 at 20:30
This is not really a solution for Ray. Ray also wants the properties into an object-array. – Martin Mulder Apr 24 '13 at 20:38
I would tend to disagree with you, Martin. The second example would allow Ray to write `bux[0][0]` or etc. So that seems to fulfill his requirements. Can you help me understand why you think otherwise? – Reacher Gilt Apr 24 '13 at 20:48

C# Refactoring the same action with different details using design patterns

4 Answers4