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Putting a Table in Edit Mode

d4jaj1
d4jaj1 asked
on
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Last Modified: 2010-05-18
When I run the code below, I get an error stating 'Datset not in Insert or Edit Mode'.  As you can see, I place the table in edit mode several times. What am I doing wrong? (By the way, I'm trying to change a field's value to False if it equals True)

procedure TfrmGList.BitBtn1Click(Sender: TObject);
begin
if table1.state = dsInactive then
   table1.Active := True;
table1.edit;
table1.disablecontrols;
table1.first;
while not table1.EOF do
  begin
    if table1.FieldByName('Select').asBoolean <> False then
       table1.edit;
       table1.FieldByName('Select').asBoolean := False;
       table1.next;
  end;
  table1.first;
  table1.enablecontrols;
end;
Comment
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Commented:
There should a "begin" following the "if" statement in the while loop. Because it is missing, the line where you modify the Select field will be activated even when the table is not in edit mode.  Here is the fixed code, note the comments :

procedure TfrmGList.BitBtn1Click(Sender: TObject);
begin
  if table1.state = dsInactive then
    table1.Active := True;
  table1.edit; // Not needed, you can remove this!
  table1.disablecontrols;
  table1.first;
  while not table1.EOF do
  begin
    if table1.FieldByName('Select').asBoolean <> False then
    begin // This was missing !!
      table1.edit;
      table1.FieldByName('Select').asBoolean := False;
      // it's safer to add table1.post here.
      table1.next;
    end; // And you need to add this as well
  end;
  table1.first;
  table1.enablecontrols;
end;

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Author

Commented:
Thanks for your quick response.  I think there is a problem though, when I run the code, nothing happens!  My system locks and the values aren't changed.  When I added the Showmessage when it finds False and after it makes the changes, it does so correctly - but goes on a continuous loop, like it never reached the EOF.   Some of the values are blank instead of false/true, could this be the problem. If I try to use ..."AsString" I get an error because the field is a logical Paradox field.  Where did I go wrong?

if table1.state = dsInactive then
   table1.Active := True;
   table1.disablecontrols;
   table1.first;
   while not table1.EOF do
     begin
       if table1.FieldByName('Select').asboolean <> False then
       Showmessage('Initial Found');  //It worked but never ended
       begin // This was missing !!
         table1.edit;
         table1.FieldByName('Select').asboolean := False;
         Showmessage('Changed');  //It worked but never ended
         //table1.post;
         table1.next;
       end; // And you need to add this as well
     end;
table1.refresh;
table1.first;
table1.enablecontrols;

Commented:
Move the table1.next out of the "if". The way it is now, it will be an infinite loop indeed.


Author

Commented:
Still doesn't work.  I commented the Disablecontrols and added the Showmessage methods so I couldl see it work.  here are still two problems, 1) The table changes values in every record, even if already equals False (although the Value Found only appears if True is found, not Blank) and 2) if never ends!  I moved the table1.next out of the If.. statement, but it still goes to the top of the grid and starts over.  Is the EOF in the wrong place?
************************************************************************
begin
table1.first;
showmessage('went first');
while not table1.EOF do
  begin
  if table1.FieldByName('Select').asBoolean <> False then
  showmessage('found value');
    begin // This was missing !!
    table1.edit;
    table1.FieldByName('Select').asBoolean := False;
    showmessage('changed');
    table1.post;
    end; // And you need to add this as well
  table1.next;
end;
end;

Commented:
Remove the ShowMessage('found value') line and everything will work.

If you can't figure out why, up the points please.

Author

Commented:
It worked!  I guess because the ShowMessage was the only statement being evaluated by the IF statement, thus the Begin statement execute regardless if teh IF statemenet returned a true or false value.

Great Job!!!

Commented:
> It worked! I guess because the ShowMessage was the only
> statement being evaluated by the IF statement, thus the Begin
> statement execute regardless if teh IF statemenet returned a > true or false value.

Exactly.

I am glad to hear that it works.
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