How to Remove non-ascii characters from data

private void button1_Click(object sender, EventArgs e)
        {
            string Data = textBox1.Text;
            char[] DataArray = Data.ToCharArray();
            string NewData = "";
            foreach (char c in DataArray)
            {
                int cint = Convert.ToInt32(c);

                if (cint <= 127 && cint >= 0)
                {
                    NewData = NewData + c.ToString();
                }
               
            }

            MessageBox.Show(NewData);

           
        }