Ejemplo n.º 1
0
        private void button6_Click(object sender, EventArgs e)
        {
            if (string.IsNullOrWhiteSpace(textBox6.Text))
            {
                PopUp.ShowInfo("textbox is empty");
                return;
            }
            if (listBox3.Items.Contains(textBox6.Text))
            {
                PopUp.ShowInfo($"{textBox6.Text} is already added");
                return;
            }

            listBox3.Items.Add(textBox6.Text);
            textBox6.Clear();
        }