Mega Code Archive
Know whether a form already exist before you dynamically create it
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Title: know whether a form already exist before you dynamically create it?
{
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;
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