TFloatField
lazarus / 16-Databases

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fmc · 2019-11-04 02:55

Every time REAL numbers are read from the db and shown in the dbgrid,
I have to convert them from scientific notation:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i TFloatField
(DM1.ZQ_AddItems.FieldByName('inventory_cost')).DisplayFormat := '####
0.00';TFloatField(DM1.ZQ_AddItems.FieldByName('inventory_sell_price'))
.DisplayFormat := '####0.00';TFloatField(DM1.ZQ_AddItems.FieldByName('
inventory_margin_contribution')).DisplayFormat := '####0.00';
This is a small thing to do, but I was wondering if there's another
way.

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Thaddy · 2019-11-04 05:27

Create your own floatfield?
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i Type 
TMyFloatField = class(TfloatField)  public    Constructor
Create(AOwner: TComponent);override;  end;   Constructor
TMyFloatFielld.Create(AOwner: TComponent);  begin    inherited
Create(AOwner);    SetDisplayFormat ('###0.00');  end;
You probably need to Register the class as well to use it beyond using
it for casting
Another way is to use attributes, although that is more complex than
the above and needs a recent trunk.

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tonyw · 2019-11-04 11:38

TFloatField just uses the RTL FloatToStr function to format real
numbers as text and which is not always that user friendly.

For float fields, I would normally use the fields editor to add the
dataset fields to the form and then define an "OnGetText" event
handler for each field for which you need to override the default
formating. The event handler could be as simple as:

procedure TMyForm.MyDataSetFieldNameGetText(
  Sender: TField; var aText: string; DisplayText: Boolean);
begin
  if DisplayText then
    aText := FormatFloat('####0.00',Sender.AsFloat)
 else
  aText := Sender.AsString
end;

The great thing about event handlers is that you can use the same
event handler for every field that you want to format the same way.

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Thaddy · 2019-11-04 13:37

@tonyw
That does not lead to reduced code and that was the question.

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devEric69 · 2019-11-04 14:42

If the event handler is obviously accessible \ public (in the TForm,
or in a central unit) from its datamodule-business-object, then the
code is serialized (potentially between all its TFloatFields), and so
is reduced. But it's less smart than including it through an
inheritance, and he'll have always to remember that it exists...
somewhere  .