[Webinar] Streamline your web hosting managementRegister Today

x
?
Solved

Delphi

Posted on 2003-10-24
4
Medium Priority
?
312 Views
Last Modified: 2012-05-04
Hi

I am new to Delphi and I have al ot of questions.  

I am writing a program that displays pager equipment information.  What happens is that there is a edit box which allows user to enter in the serial number or capcode of the pager (edEsn) and a search button in which the user clicks on to have a new window appear.  The new window (frmSrchPager) has a DBGrid with two columns.  One for Serial Number and one for Capcode.  When the user selects a serial number or capcode from the list and clicks ok, the original screen will populate with information about the pager selected.  The problem is that for every serial number, there is only one capcode but for every capcode, there could be many serial numbers.  When I search by capcode, the list would pull up a list of associating serial numbers.  However when I select one on the list, the first record on the list always populate the original screen ESNView.  If I select one in the middle of the list, the first one stills get chosen and displayed.

The code (brief)

In frmSrchPager:  The btOK procedure
Notice that Esn is String, edEsn is TEdit


          if frmEsnview.rbCapCode.Checked = True then
             begin
                frmEsnview.edEsn.Text := frmSrchpager.qrySrch.FieldByName('CAP_CODE').Text;

                Esn := frmSrchpager.qrySrch.FieldByName('SERIAL_NO').Text;

                frmEsnview.edEsn.SetFocus;
                Close;
             end
          else if frmEsnview.rbSerialNumber.Checked = True then
             begin
                frmEsnview.edEsn.Text := frmSrchpager.qrySrch.FieldByName('SERIAL_NO').Text;
                frmEsnview.edEsn.SetFocus;
                Close;
             end;
       end;

In the ESNView:  edActEnter Procedure (Display Screen)
var
   sTmpESN: string;
   bIsSearch: Boolean;
   Serial:  String;
begin
   bIsSearch := True;
   if (edActp.text = ' ') then
      begin { 1... Only the first time enter to populate the ESN query }
         if edEsn.text <> '' then {check esn validation}
            with FSerialNumVerifyQry do
               begin
                  if rbCapCode.Checked = True then
                         begin
                              Close;

                              Serial := frmSrchpager.qrySrch.FieldByName('SERIAL_NO').Text;  // HOW COME THIS DOESN'T WORK?  IT PRODUCES INACCESSIBLE VALUE

                              ParamByName('SERIAL_NO').AsString := Serial;
                              ParamByName('CAP_CODE').AsString := edEsn.Text;    // Changing Parameters for Pagers
                              Open;
                           end
                     else if rbSerialNumber.Checked = True then
                           begin
                              Close;
                              ParamByName('SERIAL_NO').AsString := edEsn.Text;
                              Open
                           end;
                     end
                 
 end; //with FSerialNumVerifyQry

         if not bIsSearch then
            begin
               edEsn.setFocus;
               Exit;
            end;

         if dsEquipInfo.Dataset <> nil then
         begin
         with (dsEquipInfo.DataSet as TQuery) do
                  if rbCapCode.Checked = True then
                     begin
                        if (active = true) then
                           close;
                        ParamByName('CAP_CODE').AsString := edEsn.text;
                        ParamByName('SERIAL_NO').AsString := frmSrchpager.Esn;  // ACCESS VIOLATION IS HERE AGAIN
                        Prepare;
                        Open;
                     end
                  else if rbSerialNumber.Checked = True then
                     begin
                       if (active = true) then
                          close;
                       ParamByName('SERIAL_NO').AsString := edEsn.Text;
                       Prepare;
                       Open;
                     end;
               end;
0
Comment
Question by:Magneto_Mystique
  • 2
2 Comments
 
LVL 27

Accepted Solution

by:
kretzschmar earned 640 total points
ID: 9619391
Hard to read ;-)

>Serial := frmSrchpager.qrySrch.FieldByName('SERIAL_NO').Text;  
// HOW COME THIS DOESN'T WORK?  IT PRODUCES INACCESSIBLE VALUE

various possibilities
-your query qrySrch is closed
-instead of .Text use .AsString
-frmSrchpager is not created
-maybe more possibilities

meikl ;-)
0
 
LVL 27

Expert Comment

by:kretzschmar
ID: 9619397
Hard to read again ;-)

>ParamByName('SERIAL_NO').AsString := frmSrchpager.Esn;  
// ACCESS VIOLATION IS HERE AGAIN

various possibilities
-frmSrchpager is not created
-What is Esn? Glabel Var? Object Attribute? Property? Object?
-maybe more possibilities

meikl ;-)
0

Featured Post

Hire Technology Freelancers with Gigs

Work with freelancers specializing in everything from database administration to programming, who have proven themselves as experts in their field. Hire the best, collaborate easily, pay securely, and get projects done right.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

A lot of questions regard threads in Delphi.   One of the more specific questions is how to show progress of the thread.   Updating a progressbar from inside a thread is a mistake. A solution to this would be to send a synchronized message to the…
Introduction The parallel port is a very commonly known port, it was widely used to connect a printer to the PC, if you look at the back of your computer, for those who don't have newer computers, there will be a port with 25 pins and a small print…
Planning to migrate your EDB file(s) to a new or an existing Outlook PST file? This video will guide you how to convert EDB file(s) to PST. Besides this, it also describes, how one can easily search any item(s) from multiple folders or mailboxes…
SQL Database Recovery Software repairs the MDF & NDF Files, corrupted due to hardware related issues or software related errors. Provides preview of recovered database objects and allows saving in either MSSQL, CSV, HTML or XLS format. Ensures recov…
Suggested Courses

611 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question