How can I shorten my if statement in a tictactoe game for checking rows etc?

I want to check my rows for x's and o's in a row.

This is what I have

 If(gameboard[0] == 1 && gameboard[1] == 1 && gameboard[2] == 1){

return winner;

This works fine for me. What I want to know is how could I reduce the amount of code here rather than having a load of if statements to check each column row especially if I decided to make the grid bigger.

I tried doing the following

    for (int i = 0; i<3; i++){
        gameboard[i] = 1;
    }
    return winner;

But this doesn't do anything. Any help is appreciated.

Thanks