How do you update a pie chart in real time in C#?

Question

Hi, I am trying to create a pie chart that updates whenever the values of the database it is connected to are changed. But everything I tried so far is not making it happen. Any suggestions on what I should do? Here is the code (I know the code is probably a bit messy but I am still a novice):

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

using System.Data.OleDb;

namespace HCI_Application

{

    public partial class Nutritional : Form

    {

        int carb = 0;

        int protein = 0;

        int fat = 0;

        OleDbConnection connection = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=\\Event Driven Programming\\HCI Application\\Nutrients.accdb");

        public Nutritional()

        {

            InitializeComponent();

        }

        private void chart1_Click(object sender, EventArgs e)

        {

        }

        private void Nutritional_Load(object sender, EventArgs e)

        {

            // TODO: This line of code loads data into the 'nutrientsDataSet.Nutrients' table. You can move, or remove it, as needed.

            this.nutrientsTableAdapter.Fill(this.nutrientsDataSet.Nutrients);

            cmbDiet.Items.Add("Standard Diet (60-30-10)");

            cmbDiet.Items.Add("Ketogenic Diet (10-45-45)");

            cmbDiet.Items.Add("Bodybuilding Diet (50-30-20)");

            cmbDiet.Items.Add("High Protein Diet (25-50-25)");

            cmbDiet.Items.Add("Zone Diet (40-30-30)");

            cmbDiet.SelectedIndex = 0;    

        }

        private void cmbDiet_SelectedIndexChanged(object sender, EventArgs e)

        {

            switch (cmbDiet.SelectedIndex)

            {

                case 0:

                    carb = 60;

                    protein = 30;

                    fat = 10;

                    break;

                case 1:

                    carb = 10;

                    protein = 45;

                    fat = 45;

                    break;

                case 2:

                    carb = 50;

                    protein = 30;

                    fat = 20;

                    break;

                case 3:

                    carb = 25;

                    protein = 50;

                    fat = 25;

                    break;

                case 4:

                    carb = 40;

                    protein = 30;

                    fat = 30;

                    break;  

            }

            connection.Open();

            OleDbCommand updateValues = new OleDbCommand("UPDATE Nutrients SET Percentage='" + carb + "' WHERE Nutrient = 'Carbohydrates'", connection);

            updateValues.ExecuteNonQuery();

            updateValues.CommandText = "UPDATE Nutrients SET Percentage='" + protein + "' WHERE Nutrient = 'Protein'";

            updateValues.ExecuteNonQuery();

            updateValues.CommandText= "UPDATE Nutrients SET Percentage='" + fat + "' WHERE Nutrient = 'Fat'";

            updateValues.ExecuteNonQuery();

            DrawChart();

            connection.Close();

        }

        private void DrawChart()

        {

            DietChart.Series["NutrientSeries"].XValueMember = "Nutrient";

            DietChart.Series["NutrientSeries"].YValueMembers = "Percentage";

        }

    }

}