Create action for different components

[Lainkes 0]

Hello,

 

I have several DateTimePicker components.

At the start, I set these to an empty value.

When I click on one of these components, I want to execute the following code :

TDateTimePicker(Sender).Format := Formatsettings.ShortDateFormat;

If this is executed, the selected date is displayed. If not, it seems to stay empty.

 

I wrote a little procedure, with this code.

How can I like this to every component. I tried to link it to the 'onChange' event, but it's not listed.

 

Thanks for your advice.

 

Greetings

 

Lainkes

[Stano 140]

Why don't you set this property when creating the form? What is your reason for this?

[Lainkes 0]

I have a checkbox, a some other components on a line. Those components are disabled at the start.

This is repeated several times.

If a user clicks a checkbox (enabled), some components on the same line are enabled and my code is executed. Then a date can be selected and can be saved to the database.

If a user clicks a checkbox (disabled), some components on the same line are disabled and the value of the DateTimePicker is set to an empty value .

At the start of the program, the DateTimePicker components are empty, so no values are written to the databasse when no checkbox are enabled.

 

Maybe there is a better solution for this problem.

 

Greetings

 

Lainkes

 

[Stano 140]

I find that suggestion very confusing. I don't know anything about the background so I can't comment.
Always keep the user in mind.

• will he understand it?
• isn't it too complicated?
• can't it be done differently?
• why don't you use DB components there? At least in the beginning, until you learn to work with it

[programmerdelphi2k 235]

@Lainkes

you can try some like this, using a "container" to avoid many search for controls...

...
  private
    procedure MyCheckBoxOnClick(Sender: TObject);
...

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
  for var i: integer := 0 to (ComponentCount - 1) do
    if (Components[i] is TCheckBox) then
      TCheckBox(Components[i]).OnClick := MyCheckBoxOnClick; // all checkbox with new OnClick...
end;

procedure TForm1.MyCheckBoxOnClick(Sender: TObject);
var
  MyParent: TPanel;
begin
  MyParent := TPanel(TCheckBox(Sender).Parent); // TPanel1,2,3
  //
  for var i: integer := 0 to (MyParent.ControlCount - 1) do
    if (MyParent.Controls[i] is TWinControl) and not(MyParent.Controls[i] = Sender) then
      TWinControl(MyParent.Controls[i]).Enabled := not TCheckBox(Sender).Checked;
end;

Edited January 29, 2023 by programmerdelphi2k

[BMSoft 0]

Hi, i'm new, and i suggest to overload the TPanel component like this :

TPanel = class(Vcl.ExtCtrls.TPanel)
  private
    FUpdateEnabled: boolean;
    FChildControl: TComponent;
    FListeChild: TList;
    FUpdateVisibility: boolean;
    FUpdateVisibilityChilds: Boolean;
    function GetChildControl: TComponent;
    function GetListeChild: TList;
    function GetUpdateEnabled: Boolean;
    function GetUpdateVisible: Boolean;
    procedure SetChildControl(const Value: TComponent);
    procedure SetListeChild(const Value: TList);
    procedure SetUpdateEnabled(const Value: Boolean);
    procedure SetUpdateVisibility(const Value: Boolean);
  protected
    procedure CMVisibleChanged(var Message: TMessage); message CM_VISIBLECHANGED;
    procedure CMEnabledChanged(var Message: TMessage); message CM_ENABLEDCHANGED;
    procedure CMDNalUpdateVisibility(var Message: TMessage); message CM_CHILD_VISIBLECHANGED;
  public
    procedure AfterConstruction; override;
    procedure BeforeDestruction; override;
    constructor Create(AOwner: TComponent); override;
    
  published
    property ChildControl: TComponent read FChildControl write FChildControl;    
    property ListeChild: TList read GetListeChild write SetListeChild;
    property UpdateEnabled: Boolean read GetUpdateEnabled write SetUpdateEnabled;
    property UpdateVisibility: Boolean read GetUpdateVisible write SetUpdateVisibility;
    property UpdateVisibilityChilds: Boolean read FUpdateVisibilityChilds write FUpdateVisibilityChilds;
  end;

And you can just use the UpdateEnabled properties to achieve that in ListeChild, just use the event EnabledChange for your component :

procedure TPanel.CMEnabledChanged(var Message: TMessage);
var i: integer;
begin
  inherited;
  if Self.FUpdateEnabled=false then exit;

  if not IsNil(Self.FChildControl) then
    TWinControl(Self.FChildControl).Enabled:= Self.Enabled;

  if (not isNil(Self.FListeChild)) and (Self.FListeChild.Count > 0) then
  begin
    for i := 0 to Self.FListeChild.Count-1 do
    begin
      if not IsNil(Self.FListeChild[i]) then
      TWinControl(Self.FListeChild[i]).Enabled:= Self.Enabled;
    end;
  end;
end;

 Hops that will help u;

Thanks