How to get record from multiple table on button click

hi,
I hope you know that how to retrieve the values from database ..........


  protected void btnSave_Click(object sender, EventArgs e)
  {
  DataBinding_Gridview(gvview, RetrieveQuery());
  }


DataBinding_Gridview(gvview, RetrieveQuery());


  private string RetrieveQuery()
  {
 
  string getquery = "";
  getquery= "SELECT  a,b,c FROM  db_table where countrycode "+lstId.selecteditem.value;
  return getquery;
  }

  private void DataBinding_Gridview(GridView gv, string query)
  {
  DataSet ds = null;
  if (gvview.PageIndex == 0)
  {
  int myindex = 0;
  gvview.PageIndex = myindex;
  }
  DatasetBinding(out ds, query);
  gv.DataSource = ds;
  gv.DataBind();
  }

  private void DatasetBinding(out DataSet ds, string query)
  {
  SqlConnection sqlcon = new SqlConnection(ConfigurationManager.AppSettings["SqlServer"]);
  SqlCommand sqlcom = new SqlCommand();
  sqlcon.Open();
  sqlcom.Connection = sqlcon;
  sqlcom.CommandType = CommandType.Text;
  sqlcom.CommandText = query;
  SqlDataAdapter sqldptr = new SqlDataAdapter(sqlcom);
  DataSet dset = new DataSet();
  sqldptr.Fill(dset);
  ds = dset;
  sqlcom.Dispose();
  sqlcon.Close();
  }

  //Page Index
  protected void gview_PageIndexChanging(object sender, GridViewPageEventArgs e)
  {
  gvview.PageIndex = e.NewPageIndex;
  DataBinding_Gridview(gvview, RetrieveQuery());

  }
  //Row Databound
  protected void gview_RowDatabound(object sender, GridViewRowEventArgs e)
  {
  int page = gvview.PageIndex + 1;
  int count = gvview.PageCount;
  }
 
  Gridview in design page:

    AutoGenerateColumns="False" onpageindexchanging="gview_PageIndexChanging"
  onrowdatabound="gview_RowDatabound" onrowcommand="gv_RowCommand"
  onrowediting="gvview_rowediting" onrowdeleting="gvview_rowdeleting" >
 
 
 
  <%#Container.DataItemIndex+1 %>
 
   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   
 
 
 
 
   
 
 


I hope it help you..........

Hi

  I will display countrycode in a listbox , and when user selects countrycode , it should display all the records in gridview from abc table where countrycode = lstbox.selectedcountry , Gridview has 1 select button and when user selects that button gridview column1 value should get stored in Textbox.


Thanks

hi,
i didn't understand your question...

implement the functionality under save button click event.....

"select last_no from table-xyz where countrycode= " +txtasasa.text;