private void textBox1_TextChanged(object sender, EventArgs e)
{
       FilterDataView();
}

private void FilterDataView()
{
      DataTable dt = new DataTable();
      DataView view = new DataView();

      dt.Columns.Add("A");
      dt.Columns.Add("B");
      dt.Columns.Add("C");

      dt.Rows.Add(new string[] { "b", "a", "a" });
      dt.Rows.Add(new string[] { "dd", "a", "a" });
      dt.Rows.Add(new string[] { "db", "a", "a" });
      dt.Rows.Add(new string[] { "db", "a", "a" });
      dt.Rows.Add(new string[] { "dddc", "a", "a" });
            
      view = dt.DefaultView;
      string asdf = "(A LIKE  '"+textBox1.Text+"*')";
      view.RowFilter = asdf; 
      dataGridView1.DataSource = view;
}