using System;

static void Main(String[] args)

    {

​

        int[][] array1 = { new int[] { 1, 2, 3 }, new int[] { 4, 5, 6 }, new int[] { 7, 8, 9 } } ;             

​

        int[][] array2 = { new int[] { 1, 2, 3 }, new int[] { 4, 5, 6 }, new int[] { 7, 8, 9 } };

​

        int[][] array3 = Concat(array1, array2);

​

    }

​

     static int[][] Concat(int[][] array1, int[][] array2)

    {

        int array1Length = array1.Length;

        int array2Length = array2.Length;

​

        int[][] result = new int[array1Length + array2Length][];

        int i = 0;

        for (; i < array1Length; i++)

            result[i] = array1[i];

​

        for (; i < array2Length + array1Length; i++)

            result[i] = array2[i - array1Length];

​

        return result;    

​

​

​

    }