Access 2d array with point in wpf C#

Question

I have a 2d array of a class. The size of array is very large (around 3000*3000) and accessing the array with ordinary row and column method is taking very much time. For this purpose, I want to use pointers to access the array.

Following is my array code:

Class definition:

Class BoxData     
{
  Size _bound;
  bool _isFilled=false;
  Color _color=Colors.White;

  public Size Bounds
  {
    get
    {
      return _bound;
    }
    set
    {
      _bound=value;
    }
  }

  public bool IsFilled
  {
    get
    {
      return _isFilled;
    }
    set
    {
      _isFilled=value;
    }
  }

  public Color FillColor
  {
    get
    {
      return _color;
    }
    set
    {
      _color=value;
    }
  }
}

Class used as array in application:

BoxData[,] boxData=new BoxData[3000,3000];

I want to access boxData with pointers.

Thanks

no you don't!...:) Suggest you post the (timed) code that is causing the problem. — Mitch Wheat, Oct 26 '10 at 09:12
Have you tried to use a Key Value Dictionary, using a key that is calculated using XY coordinates ? — Larry, Oct 26 '10 at 09:19
@Mitch: I am just getting the bounds and colors from the array using loop. — Vinod Maurya, Oct 26 '10 at 09:31
@controlbreak: No, I didn't tried Key Value. How can I use it as arrays??? — Vinod Maurya, Oct 26 '10 at 09:33
I am surprised, accessing an array is very fast. Do you mean it takes time to populate it the first time ? (3000x3000 iterations ?) — Larry, Oct 26 '10 at 09:40
@controlbreak: Yes, 3000X3000 iterations (in some cases it is 5000x5000 or even more) — Vinod Maurya, Oct 26 '10 at 09:45
@Vinod Maurya You could replace Brush instead of Color and Freeze it to enhance the performance. Though the problem is not with the array iterations, unless you access the array in Column Order. — Prince Ashitaka, Oct 26 '10 at 10:27

score 2 · Answer 1 · edited May 23 '17 at 12:04

2

Try a jagged array instead of a multi dimensional one, they are faster in Microsoft's CLR implementation

BoxData[][] boxData=new BoxData[3000][];
for (int i=0; i<3000; i++)
    boxData[i] = new BoxData[3000];

edited May 23 '17 at 12:04

Community

1
1

answered Oct 26 '10 at 09:23

Ohad Schneider

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Good advice, but you should say why. – Hans Passant Oct 26 '10 at 10:54

Larry · Answer 2 · 2010-10-26T14:35:29.177

Maybe you could use a struct instead of a class for BoxData ?

Struct is a value type: as you declare your array, everything will be populated already. You will not longer use a loop to create new BoxData() instances.

var x = new BoxData[3000,3000]; // Populated array of BoxData

Because of struct vs class restrictions, you will have to remove initializers this way...

struct BoxData
{
    Size _bound;
    bool _isFilled; // = false;
    Color _color; // = Color.White;

    public Size Bounds
    {
        get
        {
            return _bound;
        }
        set
        {
            _bound = value;
        }
    }

    public bool IsFilled
    {
        get
        {
            return _isFilled;
        }
        set
        {
            _isFilled = value;
        }
    }

    public Color FillColor
    {
        get
        {
            return _color;
        }
        set
        {
            _color = value;
        }
    }
}

...and initialize your default values using a loop will be much more faster.

for (int j = 0; j < 3000; j++)
    for (int i = 0; i < 3000; i++)
        x[i, j].FillColor = Color.White;

Access 2d array with point in wpf C#

2 Answers2