Mysql Loop freeze Window in C#

I have mysql loop

using (var conn = new MySqlConnection(connectionString))
{
    try
    {
        conn.Open();
        int count = 1;

        foreach (var value in values)
        {
            MySqlCommand cmd;
            string qu = "INSERT INTO db(val1,val2,val3,val4,val5) VALUES("+value+")";
            cmd = new MySqlCommand(qu, conn);
            cmd.ExecuteNonQuery();
            textBox1.Text = count.ToString();
            count++;
        }

        conn.Close();
    }
    catch (Exception ex)
    {
        MessageBox.Show("Error: " + ex.ToString());
    }
}

My goal is to show in textBox1 counter (loop has 18k+ rows), but when I start foreach loop my window is frozen and shows nothing until loop is end, and then show numbers in textbox, but I want to show current count number in real time.