In my code I've made a simple assumption, that if a tile is blocked then it's blocked for everybody, and I draw that tile. If it isn't blocked, it's passable for anybody, and I don't draw the tile.
This is a very simple way of doing this, and from what I can understand, you will need to draw the tile no matter what it is, but then keep track of whether it is passable for A) players and B) enemies as two separate properties.
In that case I suggest you make a Tile class, which in the Draw method just uses its Texture2D for drawing no matter what. Then you could have two boolean properties on the Tile class, e.g. PlayerPassable and EnemyPassable, where you keep track of whether the player or enemies can pass that tile.

Does that help?

Kind regards - Jakob

Thank you sir

I don't understand what you mean by making the tiles "invisible, but still known to the character in the game, only invisible to the human eye" ?
If you want something to be invisible, just don't draw it in the Draw() method. I will need a bit further clarification on what you want.
Do you mean that the player can only see a few tiles around him, and the rest is in a sort of a "fog of war" ?

Regarding your other request: if you take a look at my "map generation" tutorial
http://xnafan.net/2013/01/2d-map-generation-for-xna/
at the bottom you can find an extended version which has code to save and load maps.
This will let you have different values for different types of tile (e.g. 1 for grass, 2 for dirt, etc.) and then when you build your map, you create the tile objects with the graphics they need to draw themselves (a Texture2D) and information about whether the tile is blocked for character movement (a bool).
The best tile-engine tutorial I've found on the web is this one (by Kurt Jaegers):
http://www.xnaresources.com/default.asp?page=Tutorial:TileEngineSeries:1

Kind regards - Jakob

How do u do that sir? Thank you

And if you don't mind, i would like to know how to change the graphics in the tiles, but in the same array. Or how to make the tiles that we just array it and visible to make it invisible, but still known to player in the game, but not visible while user sees it. So, basically invisible tiles, but still known by the character in the game, only invisible to the human eyes.

Example: The enemy is on tile [3,2], and in the [5,2] there is a tile (grass graphic), the enemy move from the [3,2] to [5,2], but the human eyes still see the tile on [5,2] for prevent the enemy to move ahead to [6,2]. What i mean is, the tile on [5,2] is invisible to the human eyes.

Is it possible? And if possible, i would like to know how to do it in XNA.

Thank you very much sir.

Best Regards,

Frendy

Yup - that is very much possible.
Did you solve it when looking at the "saving and loading data" tutorial?

Otherwise I can make you a codesample

Kind regards - Jakob

And, if you don't mind,t i have a question regarding the map.. is it possible to make a map constant and not randomly?
So, it is like (example): 0 is for unblocked tiles, and 1 is for blocked tiles. and i have an array like this:

private var Tiles:Array = new Array();

Tiles = [0,0,0,1,1,1,1,1,0,1], <-- this is for row 1
[0,0,0,0,0,0,0,1,1,1] <-- this is for row 2

And that Tiles Array will be for our map, and 0 for unblocked tiles, and 1 for blocked tiles.
Could you please teach us including me how to do it sir? So, basically the map is not random, but we already define it. Thank you

Glad you like it!
I didn't know what a "2D sandbox" game meant before reading your post and Googling it.
Could you be more specific as to what you would like to see?
The way I understand it, most of the games are like Terraria, Starbound and/or Windforge.
Is that what you're looking for?
In that case, I'm guessing that a lot of the terrain could be generated using the Tile engine technique.
So what else do you need? AI? Random terrain generation? 😀