How can I get the Xwinnerform to stay on top an keep the main form from being clicked, I tried ShowDialog but I cant get it to work.

 static public bool CheckWinner(Button[] myControls)
            {
                //bolean statement to check for the winner 
                bool gameOver = false;
                for (int i = 0; i < 8; i++)
                {
                    int a = Winners[i, 0];
                    int b = Winners[i, 1];
                    int c = Winners[i, 2];

                    Button b1 = myControls[a], b2 = myControls[b], b3 = myControls[c];
                    if (b1.Text == "" || b2.Text == "" || b3.Text == "")
                        continue;
                    if (b1.Text == b2.Text && b2.Text == b3.Text)
                    {
                        xWinnerForm xWinnerForm = new xWinnerForm();
                        xWinnerForm.ShowDialog(b1.Text + " is the Winner");

                    }



                }


                       return gameOver;
            }
        enter code here