C# :: Why Filtering In Data Grid Don't Work

why filtering don't work??

This is code for load data into dataGridView

private void Izvestaj_Load(object sender, EventArgs e) {
connection.ConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:UsersTomyDesktopzadatak2zadatak2fedek_OldVersion(2002-2003).mdb;User Id=admin;Password=;";
dt = new DataTable();
OleDbDataAdapter sda = new OleDbDataAdapter("SELECT korisnici.korisnik,dogadjaji.dogadjaj,Tomislav.Datum

[Code] .....

And this is code for filtering by typing into textbox, when type nothing happening

private void textBox3_TextChanged(object sender, EventArgs e) {
DataView DW2 = new DataView(dt);
DW2.RowFilter = string.Format("dogadjaji.dogadjaj LIKE '%{0}%'", textBox3.Text);
dataGridView1.DataSource = DW2;

[Code] .....

And this is by filtering on dataPickers, range of date, and show me what happens on that dates, but show me exception when click button

private void button1_Click(object sender, EventArgs e) {
if(dateTimePicker1.Value>dateTimePicker2.Value) {
MessageBox.Show("Takav opseg nije moguc. Datum Od mora biti veci od datuma Do.", "Opseg datuma", MessageBoxButtons.OK, MessageBoxIcon.Error);

[code].....