If I use Field InvoiceDate OnGetText it fails (data disappears)

...

 for i:= 0 to tblPurchases.FieldDefs.Count -1 do begin
   try
     fld:= tblPurchases.FieldDefs.Items[i].CreateField(tblPurchases); // reusing fld over and over ???
     //
     if UpperCase(fld.FullName) = UpperCase('InvoiceDate') then begin
       TDateTimeField(fld).OnGetText:=     GetText2;
     end;

...

procedure TUniMainModule.GetText2(Sender: TField; var Text: String; DisplayText: Boolean);
begin
 if TField(Sender).AsDateTime < EncodeDate(1900, 1, 1) then begin
   Text:= '';
   DisplayText:= False;
 end else begin
   Text:= DateToStr(TField(Sender).AsDateTime);
   DisplayText:= True;
 end;
end;

Andrew


I'm very puzzled. I don't know if its just my newsreader but it doesn't look as though you're assigning the address of GetText2 to OnGetText. I also can't understand the loop. A table can only have one column called InvoiceDate so why not just address it directly?

Roy Lambert

Roy, my idea was to paint Date.Text blank when date is null or pre 1900 (instead of 31/12/1899) - of course all NumericField code works correctly but when DateTimeField is involved it strips out all data.

 // Set Persistent Float Field Display Text
 for i:= 0 to tblPurchases.FieldDefs.Count -1 do begin
   try
     fld:= tblPurchases.FieldDefs.Items[i].CreateField(tblPurchases); // reusing fld over and over ???
     //
     if UpperCase(fld.FullName) = UpperCase('InvoiceDate') then begin
//        TDateTimeField(fld).OnGetText:= GetText2;
     end;
     //
     if UpperCase(fld.FullName) = UpperCase('Amount') then begin
       TNumericField(fld).DisplayFormat:= '######.##';
       TNumericField(fld).OnGetText:= GetText;
     end;
     //
     if UpperCase(fld.FullName) = UpperCase('GST') then begin
       TNumericField(fld).DisplayFormat:= '######.##';
       TNumericField(fld).OnGetText:= GetText;
     end;
     //
     if UpperCase(fld.FullName) = UpperCase('Adjustment') then begin
       TNumericField(fld).DisplayFormat:= '######.##';
       TNumericField(fld).OnGetText:= GetText;
     end;
     //
     if UpperCase(fld.FullName) = UpperCase('Paid') then begin
       TNumericField(fld).DisplayFormat:= '######.##';
       TNumericField(fld).OnGetText:= GetText;
     end;
     //
     if UpperCase(fld.FullName) = UpperCase('ReconciledDate') then begin
//        TDateTimeField(fld).OnGetText:= GetText2;
     end;
     //
     if UpperCase(fld.FullName) = UpperCase('Owing') then begin
       TNumericField(fld).DisplayFormat:= '######.##';
       TNumericField(fld).OnGetText:= GetText;
     end;
     //
   except
     on E: Exception do begin
       s:= E.Message;
     end;
   end;
   //
 end; // for
 tblPurchases.FieldDefs.Update;

Tim, would you care to wade in - Thanks - Andy

Andrew


Just so you know this is Delphi not ElevateDB.I know I had problems with a component where I did this and I'll have a look this afternoon

Roy Lambert

Andrew


I've been having a look and I've made a couple of changes to your code - see below.  I'm on an old version of Delphi (D2007)  which may or may not be significant, but the code works and I get exactly what I'd expect to see.


procedure TForm1.GetText2(Sender: TField; var Text: string; DisplayText: Boolean);
begin
if Sender.AsDateTime < EncodeDate(2020, 1, 1) then begin
 Text := '';
 DisplayText := True; <<<<<<<<<<<<<<<<<<<<<<<<

end else begin
 Text := DateToStr(Sender.AsDateTime);
 DisplayText := True;
end;
end;

procedure TForm1.FormCreate(Sender: TObject);
var
i: integer;
fld: TField;
begin
Test.FieldDefs.Update; <<<<<<<<<<<<<<<<<<<<<<
for i := 0 to Test.FieldDefs.Count - 1 do begin
 fld := Test.FieldDefs.Items[i].CreateField(Test); // reusing fld over and over ???
     //
 if UpperCase(fld.FullName) = UpperCase('_Date') then TDateTimeField(fld).OnGetText := GetText2;
end;
Test.Open;
end;

Roy Lambert

Roy, either way once "TDateTimeField(fld).OnGetText:=" is set then all data disappears.

Debugging shows GetText2 firing and setting text as expected but no data is shown from table ???.

I even tried this

procedure TUniMainModule.GetText2(Sender: TField; var Text: String; DisplayText: Boolean);
begin

Exit; <<<<<<<<<<<<

 if Sender.AsDateTime < TestDateTime then begin
   Text:= '';
   DisplayText:= True;
 end else begin
   Text:= DateToStr(Sender.AsDateTime);
   DisplayText:= True;
 end;
end;

OK, this is what is killing it

reusing fld over and over

Andrew


Its not something I tested for but when I think about it only the last instance would probably "stick". At least you've solved the problem.

Roy Lambert