Question

Is it possible, in C#, to convert a multi-dimensional array into a 1D array without having to copy all the elements from one to the other, something like:

int[,] x = new int[3,4];
int[] y = (int[])x;

This would allow the use of x as if it were a 12-element 1D array (and to return it from a function as such), but the compiler does not allow this conversion.

As far as I’m aware, a 2D array (or higher number of dimensions) is laid out in contiguous memory, so it doesn’t seem impossible that it could work somehow. Using unsafe and fixed can allow access through a pointer, but this doesn’t help with returning the array as 1D.

While I believe I can just use a 1D array throughout in the case I’m working on at present, it would be useful if this function was part of an adapter between something which returns a multidimensional array and something else which requires a 1D one.

Answer 1

You can’t, it’s not possible in C# to convert array’s this way. You maybe could do it by using a external dll ( C/C++ ), but then you need to keep your array at a fixed location.

Speed

Generally i would advice to avoid using a 2D array because theese are slow in C#, better use jagged-array or even better single dimensionals with a little bit of math.

Int32[] myArray = new Int32[xSize * ySize];

// Access
myArray[x + (y * xSize)] = 5;