Bulk Update in Grid

Question

Hi All,

I have a grid where I use a checkbox for bulk update by selecting multiple rows. Now I placed a footer template with the textbox below the grid. Assume like I select two rows in the grid(using checkbox) and when I enter values in the textbox in footertemplate below the grid, then changes have to be reflected to the selected rows in the grid for the columns(Saved to the DB). I use the below update query to update selected checkbox rows to DB and how can I do that to my footertemplate rows which has textbox for update. Any suggestions pls?

 protected void Save(object sender, EventArgs e)
  {
  foreach (GridViewRow row in GridView1.Rows)
  {
  if (row.RowType == DataControlRowType.DataRow)
  {
  bool isChecked = row.Cells[0].Controls.OfType<CheckBox>().FirstOrDefault().Checked;
  if (isChecked)
  { 
  SqlCommand cmd = new SqlCommand("UPDATE AppInvent_Test SET Name = @Name, Designation = @Designation, City = @City WHERE EmpID = @EmpID");
  cmd.Parameters.AddWithValue("@EmpID", row.Cells[1].Controls.OfType<TextBox>().FirstOrDefault().Text);
  cmd.Parameters.AddWithValue("@Name", row.Cells[2].Controls.OfType<TextBox>().FirstOrDefault().Text);
  cmd.Parameters.AddWithValue("@Designation", row.Cells[3].Controls.OfType<TextBox>().FirstOrDefault().Text);
  cmd.Parameters.AddWithValue("@City", row.Cells[4].Controls.OfType<TextBox>().FirstOrDefault().Text);
  this.ExecuteQuery(cmd, "SELECT");
  }
  }
  }
  this.FillVendorGrid();
  }