Why is output not working in Winsows Forms?

Question

C++ / C#

private void buttonitog_Click(object sender, EventArgs e)
        {
            double h = Convert.ToDouble(textBox1.Text);
            double ves;
            if(comboBox1.SelectedIndex == 0)
            {
                ves = (h - 100) * 1.5;
                 label1..Text = string.Format(ves);
            }
            else if(comboBox1.SelectedIndex == 1)
            {
                ves = (h - 110) * 1.5;
                label1.Text = string.Format(ves);
            }
            
        }

Answer 1

Because you need to read the documentation

Answer 2

Label1.. Text two dots.