using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Data;
    using System.Drawing;
    using System.Linq;
    using System.Text;
    using System.Threading.Tasks;
    using System.Windows.Forms;
                    
    namespace ComboBox_Data_Add_Remove
    {
        public partial class Form1 : Form
        {
            public Form1()
            {
                InitializeComponent();
            }
            private void button1_Click(object sender, EventArgs e)
            {   
                comboBox1.Items.Add(textBox1.Text);
            }
            private void button2_Click(object sender, EventArgs e)
            {
                comboBox1.Items.Remove(textBox1.Text);
            }
        }
    }