До динамического создания формы узнать, существует ли она

{codecitation class=»brush: pascal; gutter: false;» width=»600px»}

Оформил: DeeCo

Автор: http://www.swissdelphicenter.ch

{

Q: How to know whether a form already exist before I dynamically create it ?

A: See the Forms and FormCount property of TScreen. You can iterate

through the forms, and test to see if your form is there.

}

function IsFormOpen(const FormName : string): Boolean;

var

i: Integer;

begin

Result := False;

for i := Screen.FormCount — 1 DownTo 0 do

if (Screen.Forms[i].Name = FormName) then

begin

Result := True;

Break;

end;

end;

// Example: Showing a TForm.

// First check, if the Form (here Form2) is open. If not, create it.

procedure TForm1.Button1Click(Sender: TObject);

begin

if not IsFormOpen(‘Form2’) then

Form2 := TForm2.Create(Self);

Form2.Show

end;

{ For MDI Children }

function IsMDIChildOpen(const AFormName: TForm; const AMDIChildName : string): Boolean;

var

i: Integer;

begin

Result := False;

for i := Pred(AFormName.MDIChildCount) DownTo 0 do

if (AFormName.MDIChildren[i].Name = AMDIChildName) then

begin

Result := True;

Break;

end;

end;

// Example: Showing a MDI Child.

// First check, if the MDI Child is open. If not, create it.

procedure TForm1.Button2Click(Sender: TObject);

begin

if not IsMDIChildOpen(Form1, ‘MyMDIChild’) then

MyMDIChild := TMyMDIChild.Create(Self);

MyMDIChild.Show;

MyMDIChild.BringToFront;

end;

{/codecitation}

Добавить комментарий