title: dataTable.DefaultView.Rowfilter always returning first row
body: <p>I've been trying to make a search function for a dataTable. My problem is that the first row of the table is ALWAYS within the filtered rows, even when the boolean column is actually changed to a zero.
  Here is my search code:</p>
  
  <pre><code>private void buscar()
      {
          DataTable dataTable;
          if (!verTodos)
          {
              dataTable = DBHelper.Instance.ProductosConStock();
          }
          else
          {
              dataTable = DBHelper.Instance.ProductosTodos();
          }
          dataGridProductos.DataSource = dataTable.DefaultView;
          foreach (DataGridViewRow row in dataGridProductos.Rows)
          {
              if (row.Cells[0].Value.ToString().ToUpper().Contains(txtBusqueda.Text.ToString().ToUpper()) ||
                  row.Cells[1].Value.ToString().ToUpper().Contains(txtBusqueda.Text.ToString().ToUpper()) ||
                  row.Cells[2].Value.ToString().ToUpper().Contains(txtBusqueda.Text.ToString().ToUpper()))
              {
                  row.Cells[4].Value = 1;
              }
              else
              {
                  row.Cells[4].Value = 0;
              }
          }
          dataTable.DefaultView.RowFilter = "mostrar = 1";
      }
  </code></pre>