How to get all the numbers from 2d array that pass the if condition into 1d array

sorry for noob question :). I've got 2d array 3x3 filled with random numbers (-5,5)

for (int i = 0; i < 3; i++)
                for (int j = 0; j < 3; j++)
                {
                    dPole[i, j] = nc.Next(-10, 10);

I want all the numbers that are positive and then save them into 1d array:

foreach (int j in dPole)
            {


                if (j > 0)
                {
                    Console.WriteLine(j);
                    for (int i = 0; i < sizeOf1dArray; i++)

                            jPole[i] = j;
                }
            }

Output of Console.WriteLine(j)- to check if the condition is right:

6
2
5
6
9
8

Output of 1d Array:

8
8
8
8
8
8

Only the last number is saved into array. Why? Thanks.