C# Combobox and textbox

[TanJJ]

My i ask, how to do when we select a selected item in Combobox and the selected item may or may not to fill in the Textbox?
For example, select a item in Combobox and no need to do a remark in it or can do remark.

[Luk3r]

        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            textBox1.Text = comboBox1.SelectedItem.ToString();
        }