Destroying Tedits at runtime

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Destroying Tedits at runtime

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#1 by (2 votes)
#2 by (1 votes)

1

I have an application that creates TEdits from 1 to 15 I would like them to disappear, but when the person clicks the button to create them they come back ..

They were created as follows:

ArrayEdit[x] := TEdit.Create(Self);
ArrayEdit[x].Parent:= Self;
ArrayEdit[x].Left := 100 + x * 50;
ArrayEdit[x].Top := 124;
ArrayEdit[x].Width := 41;
ArrayEdit[x].Height :=24;
ArrayEdit[x].Name := 'edit'+ inttostr(x+20);

And I'm destroying them as follows:

 for i := ComponentCount - 1 downto 0 do
    begin
      If (Components[i] is tedit) then
        Tedit(Components[i]).Destroy;
    end;

The problem is as follows, it gives an Access Violation error and also seeu destroy the edits will I have to close the application to use them again, any ideas?

delphi

asked by anonymous 06.10.2015 / 14:29

2 answers

1

With this code here (which uses the code you passed), everything is ok.

unit Unit2;

interface

uses
  Winapi.Windows,
  Winapi.Messages,
  System.SysUtils,
  System.Variants,
  System.Classes,
  Vcl.Graphics,
  Vcl.Controls,
  Vcl.Forms,
  Vcl.Dialogs,
  Vcl.StdCtrls;

type
  TForm2 = class(TForm)
    btn1: TButton;
    btn2: TButton;
    procedure FormCreate(Sender: TObject);
    procedure btn2Click(Sender: TObject);
    procedure btn1Click(Sender: TObject);
  private
    procedure criarEdits;
  public

  end;

var
  Form2: TForm2;

implementation

{$R *.dfm}

procedure TForm2.btn1Click(Sender: TObject);
var
  i : Integer;
begin
    for i := ComponentCount - 1 downto 0 do
    begin
        If (Components[i] is tedit) then
            Tedit(Components[i]).Destroy;
    end;
end;

procedure TForm2.btn2Click(Sender: TObject);
begin
    criarEdits;
end;

procedure TForm2.criarEdits;
var
  i : Integer;
  arrayEdit : array[1..15] of TEdit;
begin
  for i := 1 to 15 do
  begin
    ArrayEdit[i] := TEdit.Create(Self);
    ArrayEdit[i].Parent:= Self;
    ArrayEdit[i].Left := 100 + i * 50;
    ArrayEdit[i].Top := 124;
    ArrayEdit[i].Width := 41;
    ArrayEdit[i].Height :=24;
    ArrayEdit[i].Name := 'edit'+ inttostr(i+20);
  end;
end;

end.

06.10.2015 / 15:46

How to create expression that returns 1,12,123,1234 in Python Transform query into dataframe [sqlalchemy + pandas]

score 2 · Accepted Answer

Some comments:

Do not run Destroy directly, prefer to use Free , which runs Destroy only after checking if the component is actually allocated.
What do you call "fade away" is actually destroying the component? Would it not be enough to make them invisible?

To make them invisible, you just have to do:

for i := ComponentCount - 1 downto 0 do
begin
  If (Components[i] is tedit) then
    Tedit(Components[i]).Visible:= false;
end;

And to make them visible again, it would just do

for i := ComponentCount - 1 downto 0 do
begin
  If (Components[i] is tedit) then
    Tedit(Components[i]).Visible:= true;
end;