PLEASE PLEASE HELP ME ,ITS VERY URGENT...

Question

Hi friends,

I am working on checkbox in GRIDVIEW. I want to delete all the selected records... I have this code below for your reference... Please help me to make it work ... Thanks....

protected void btnDelete_Click(object sender, EventArgs e)
{
  string currentrow;
  for (int index = 0; index <= GridView1.Rows.Count - 1; index++)
  {
  CheckBox cb =  (CheckBox)GridView1.Rows[index].FindControl("chkDelete");
  if (cb.Checked)
  {
  currentrow = GridView1.DataKeys[index].Value.ToString();
  string constr = @"Data Source=OM;Initial Catalog=TestDB;Integrated    Security=True";
  string query = @"Delete FROM Categories where CategoryID='" + currentrow + "'";
  SqlConnection con = new SqlConnection(constr);
  SqlCommand cmd = new SqlCommand(query);
  SqlDataAdapter da = new SqlDataAdapter(query, constr);
  DataSet ds = new DataSet();
  da.Fill(ds, "Categories");

  GridView1.DataSource = ds.Tables["Categories"];
  GridView1.DataBind();

  }
 
  }

 
  }