如何复制 C# 3D 锯齿状数组

Question

I need to (initially) copy a C# 3D jagged array, foos , to another 3D array (and eventually add x, y, z dimensions). I thought I could use the same syntax/logic to copy foos as was used to build foos as I've done below (where row = 2, col = 3, z = 4):

private static void copyFooArray(Foo[][][] foos, ref Foo[][][] newArray)
{
    for (int row = 0; row < foos.Length; row++)
    {
        newArray[row] = new Foo[foos[row].Length][];

        for (int col = 0; col < foos[row].Length; col++)
        {
            newArray[row][col] = new Foo[foos[row][col].Length];

            for (int z= 0; z< foos[row][col].Length; z++)
            {
                newArray[row][col][z] = new Foo();
                newArray[row][col][z].member = foos[row][col][z].member;
            }
        }
    }            
        Console.Read();
}

but I'm getting Index was outside the bounds of the array. on this line:

newArray[row] = new Foo[foos[row].Length][];

Why?

Foo Class:

public class Foo
{ 
    public string member;
}

Thanks.

Answer 1

It doesn't look like your referenced array is being initialized properly. In order to set the value, your newArray must be initialized as the same size of your original.

For this to work you'd need to pass in something like this:

Foo[][][] firstFoo = new Foo[10][][];
Foo[][][] fooToCopy = new Foo[firstFoo.Length][][];

copyFooArray(firstFoo, ref fooToCopy);

Also, the ref keyword is unnecessary since arrays are passed by reference in c# anyways.

Answer 2

In addition to the fix presented in the accepted answer, here's a faster way to do that:

   public static int[][][] Copy(int[][][] source)
    {
        int[][][] dest = new int[source.Length][][];
        for (int x = 0; x < source.Length; x++)
        {
            int[][] s = new int[source[x].Length][];
            for (int y = 0; y < source[x].Length; y++)
            {
                int[] n = new int[source[x][y].Length];
                int length = source[x][y].Length * sizeof(int);
                Buffer.BlockCopy(source[x][y], 0, n, 0, length);
                s[y] = n;
            }
            dest[x] = s;
        }
        return dest;
    }