DataGridView AutoComplete TextBox in C#

This tutorial will show you how to set your textbox support autocomplete in DataGridView using C#.NET

As you see, AutoCompleteCustomSource, AutoCompleteMode and AutoCompleteSource properties to perform an auto-completion of a user's input strings by comparing the prefix letters entered with the prefix of all strings in the data source.

using System;
using System.Collections.Generic;
using System.Windows.Forms;

namespace CSharpCodeDemo
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            string[] row = new string[] { "1", "Product 1", "150" };
            dataGridView1.Rows.Add(row);
            row = new string[] { "2", "Product 2", "200" };
            dataGridView1.Rows.Add(row);
            row = new string[] { "3", "Product 3", "350" };
            dataGridView1.Rows.Add(row);
            row = new string[] { "4", "Product 4", "400" };
            dataGridView1.Rows.Add(row);
        }

        private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
        {
            string title = dataGridView1.Columns[1].HeaderText;
            if (title == "Product Name")
            {
                TextBox txt = e.Control as TextBox;
                if (txt != null)
                {
                    txt.AutoCompleteMode = AutoCompleteMode.Suggest;
                    txt.AutoCompleteSource = AutoCompleteSource.CustomSource;
                    AutoCompleteStringCollection DataCollection = new AutoCompleteStringCollection();
                    //Add data source to textbox control
                    AddItems(DataCollection);
                    txt.AutoCompleteCustomSource = DataCollection;       
                }
            }
         }

        public void AddItems(AutoCompleteStringCollection data)
        {
            data.Add("Product 1");
            data.Add("Product 2");
            data.Add("Product 3");
            data.Add("Product 4");
        }
    }
}

Each time you click on the DataGridView in the Product Name column, the list of products is automatically populated allowing you to select the product