how to search data in datagridview using ado.net

Hello,

I think the code is working fine. Based on the code that you provided, I see you initialized ds = new DataSet(); but I didn't see where ds is being populated before using it on this line
dv.Table = ds.Tables["Physio_cureTable"]; it should work if the ds object is not empty.

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 DataView_RowFilter
{
    public partial class Form1 : Form
    {
        string ConnectionString = System.Configuration.ConfigurationSettings.AppSettings["dsn"];
        OleDbCommand com;
        OleDbDataAdapter oledbda;
        DataSet ds;
       
        string str;
        public Form1()
        {
            InitializeComponent();
        }

        private void btndisplayall_Click(object sender, EventArgs e)
        {
            OleDbConnection con = new OleDbConnection(ConnectionString);
            con.Open();
            str = "select * from student";
            com = new OleDbCommand(str, con);
            oledbda = new OleDbDataAdapter(com);
            ds = new DataSet();
            oledbda.Fill(ds, "student");
            dataGridView1.DataSource = ds;
            dataGridView1.DataMember = "student";
            con.Close();
        }

        private void btndisplay_Click(object sender, EventArgs e)
        {
            DataTable dt;
            dt = ds.Tables["student"];
            DataView dv = new DataView(dt);
            dv.RowFilter = "sname='" + textBox1.Text + "'";
            dataGridView1.DataSource = dv;
        }
    }
}