Hello
You have to check each of cell text value in your TextChanged event and Code something like below
private void textBox1_TextChanged(object sender, EventArgs e)
{
foreach (DataGridViewRow row in dataGridView.Rows)
{
if (row.Cells[0].Value.ToString() == "someVal")
{
row.DefaultCellStyle.BackColor = Color.Yellow;
}
}
}