При выводе min / max / среднего значения выводятся 0-ли

Вот код:

class one //основной для роботы с массивами символов
{
    public double Max;
    public double Min;
    public double[] SortArr = new double[10];
}

public double[] BubbleSort(double[] array)
{
    double temp;
    for (int i = 0; i < array.Length; i++)
    {
        for (int j = 0; j < array.Length - 1 - i; j++)
        {
            if (array[i] > array[j + 1])
            {
                temp = array[j];
                array[j] = array[j + 1];
                array[j + 1] = temp;
            }
        }
    }
    for (int i = 0; i < array.Length; i++)
    {
        richTextBox1.Text += (array[i].ToString() + " ");
    }
    
    return array;
}
public double method(double min, double max)
{
    textBox1.Text += ((string)"Min = " + min + " " + "Max = " + max);
    return 0;
}

public double BubbleSortOut(double[] SortOut)
{
    for (int i = 0; i < SortOut.Length; i++)
    {
        richTextBox1.Text += (SortOut[i].ToString() + " ");
    }
    return 0;
}

private void button1_Click(object sender, EventArgs e)
{
    int SumCell = 0;
    textBox1.Visible = false;
    one One = new one();    
    
    bool indic = true;
    var _listOfTrad = new List<Double>();

    for (int a = 0; a < dataGridView1.Rows.Count - 1; a++)
    {
        if (dataGridView1.Rows[a].Cells[0].Value != null)
        {
            _listOfTrad.Add(Convert.ToDouble(dataGridView1[0, a].Value));
        }
        else
        {
            MessageBox.Show("Not enough values!");
            indic = false;
        }
    }

    One.Min = _listOfTrad.Min();
    One.Max = _listOfTrad.Max();
    
    _listOfTrad.Average();

    for (int i = 0; i < dataGridView1.RowCount; i++) //кол-значний в dataGrid
    {
        for (int y = 0; y < dataGridView1.ColumnCount; y++)
        {
            if (dataGridView1[y, i].Value != null)
            {
                SumCell = SumCell + 1;
            }
        }
    }

    double[] array = new double[SumCell];
    _listOfTrad.CopyTo(array);

    double[] SortArray = new double[SumCell];
    SortArray = BubbleSort(array);
    SortArray.CopyTo(One.SortArr, 0);
}

private void button2_Click(object sender, EventArgs e)
{
    textBox1.Visible = true;
    one One = new one();
    method(One.Min, One.Max);
}

private void button3_Click(object sender, EventArgs e)
{
    textBox1.Visible = true;
    one One = new one();
    BubbleSortOut(One.SortArr);
}

private void button4_Click(object sender, EventArgs e)
{
    textBox1.Visible = true;
    one One = new one();
    textBox1.Text += (One.SortArr.Average());
}