Help please... C# search at excel file

Question

I've watched a tutorial on youtube that explain how to search in an excel file but when I search for a specific value in a row I must type at the search box column name = 'value at the row' and the column name must be a single word, not 2 words split with space or I must write column name like '%value%' to get similar results. when I search for a specific value in a row

 

 

to search for similar results

 

 

column name must be a single word

 

 

First: How I can search by writing a specific keyword at any row. Second: How I can load column names at combo box and search by column name and make it optional to select column. Code:

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 excel
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private void label1_Click(object sender, EventArgs e)
        {
        }
        private void Form1_Load(object sender, EventArgs e)
        {
        }
        private void btnOpen_Click(object sender, EventArgs e)
        {
            using(OpenFileDialog ofd = new OpenFileDialog() { Filter = "Excel Workbook|*.xlsx",Multiselect = false})
            {
                if (ofd.ShowDialog() == DialogResult.OK)
                {
                    Cursor.Current = Cursors.WaitCursor;
                    DataTable dt = new DataTable();
                    using(XLWorkbook workbook = new XLWorkbook(ofd.FileName))
                    {
                        bool isFirstRow = true;
                        var rows = workbook.Worksheet(1).RowsUsed();
                        foreach(var row in rows)
                        {
                            if (isFirstRow)
                            {
                                foreach (IXLCell cell in row.Cells())
                                    dt.Columns.Add(cell.Value.ToString());
                                isFirstRow = false;
                            }
                            else
                            {
                                dt.Rows.Add();
                                int i = 0;
                                foreach (IXLCell cell in row.Cells())
                                    dt.Rows[dt.Rows.Count - 1][i++] = cell.Value.ToString();
                            }
                        }
                        dataGridView1.DataSource = dt.DefaultView;
                        lblTotal.Text = $"Total Records:{dataGridView1.RowCount}";
                        Cursor.Current = Cursors.Default;
                    }
                }
            }
        }
        private void btnSearch_Click(object sender, EventArgs e)
        {
            try
            {
                DataView dv = dataGridView1.DataSource as DataView;
                if (dv != null)
                    dv.RowFilter = txtSearch.Text;
            }
            catch(Exception ex)
            {
                MessageBox.Show(ex.Message, "Message", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }
        private void txtSearch_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (e.KeyChar == (char)13)
                btnSearch.PerformClick();
        }
        private void label2_Click(object sender, EventArgs e)
        {
        }
        private void txtSearch_TextChanged(object sender, EventArgs e)
        {
        }
        private void dataGridView1_CellContentClick(object sender, DataGridViewCellEventArgs e)
        {
        }
    }
}