Search index of value in array using Binary Search

        protected void btnTemp_Click(object sender, EventArgs e)

        {

            int[] intAry = new int[] { 8, 5, 3, 4, 8, 7, 2, 12, 50, 24, 20, 41, 21, 37, 40 };

            intAry = intAry.OrderBy(t => t).ToArray();

            int index = BinarySearch(intAry, Convert.ToInt32(txtSec.Value));

        }

        int BinarySearch(int[] aryNum, int val)

        {

            int index = -1;

            int start, end;

            start = 0;

            end = aryNum.Length;

            while (true)

            {

                int Mid = (end + start) / 2;               

                if (aryNum[Mid] == val)

                {

                    index = Mid;

                    return index;

                }

                else if (aryNum[Mid] > val)

                {

                    end = Mid - 1;                  

                }

                else if (aryNum[Mid] < val)

                {

                    start = Mid + 1;                  

                }

                if (start == end)

                {

                    if (aryNum[start] == val)

                    {

                        index = start;

                        return index;

                    }

                    break;

                }

            }

            return index;

        }