How to resize multidimensional (2D) array in C#? -

i tried following returns screwed array.

    t[,] resizearray<t>(t[,] original, int rows, int cols)     {         var newarray = new t[rows,cols];         array.copy(original, newarray, original.length);         return newarray;     } 

most methods in array class work one-dimensional arrays, have perform copy manually:

t[,] resizearray<t>(t[,] original, int rows, int cols) {     var newarray = new t[rows,cols];     int minrows = math.min(rows, original.getlength(0));     int mincols = math.min(cols, original.getlength(1));     for(int = 0; < minrows; i++)         for(int j = 0; j < mincols; j++)            newarray[i, j] = original[i, j];     return newarray; } 

to understand why doesn't work array.copy, need consider layout of multidimensional array in memory. array items not really stored bidimensional array, they're stored contiguously, row after row. array:

{ { 1, 2, 3 },   { 4, 5, 6 } } 

is arranged in memory that: { 1, 2, 3, 4, 5, 6 }

now, assume want add 1 more row , 1 more column, array looks this:

{ { 1, 2, 3, 0 },   { 4, 5, 6, 0 },   { 0, 0, 0, 0 } } 

the layout in memory follows: { 1, 2, 3, 0, 4, 5, 6, 0, 0, 0, 0, 0 }

but array.copy treats arrays one-dimensional. msdn says:

when copying between multidimensional arrays, array behaves long one-dimensional array, rows (or columns) conceptually laid end end

so when try copy original array new one, copies 1 memory location other, gives, in one-dimensional representation:

{ 1, 2, 3, 4, 5, 6, 0, 0, 0, 0, 0, 0 }.

if convert two-dimensional representation, following:

{ { 1, 2, 3, 4 },   { 5, 6, 0, 0 },   { 0, 0, 0, 0 } } 

this why you're getting screwed array... note work property if changed number of rows, not number of columns.