asked on

Delphi form overriding form inheritance

Good day

I have frmMain and frmCapture that are inherited from frmMain.

In frMain on key press event I call forms depending on the short cut key.

But when frmCapture are visible, then frmCapture must ignore the key press event that happens in frmMain, or it must ignore the VK_F5 key.

Is this possible.

Geert G

in frmMain you are using KeyPreview ?
in frmCapture set it off

or provide a little more code so we can see what you ment ...

MerijnB

Like Geert suggests, set frmMain.KeyPreview to true
in frmMain, change the Key to 0 after you've handled it:

procedure frmMain.FormKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState);
begin
 // do what you want to do with the key
 Key := 0; // stops other controls from handling it
end;

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henryreynolds

ASKER

in frmMain I have the following

procedure TfrmMain.FormKeyUp(Sender: TObject; var Key: Word;
Shift: TShiftState);
begin
if Key = VK_F3 then
begin
Application.CreateForm(TfrmAlphaSearch, frmAlphaSearch);
try
frmAlphaSearch.ShowModal();
finally
frmAlphaSearch.Free;
end;
end;

if Key = VK_F5 then
begin
Application.CreateForm(TfrmSettlements, frmSettlements);
try
frmSettlements.ShowModal();
finally
frmSettlements.Free;
end;
end;
end;

When I am in frmSettlements I dont want to allow F5 -> to call again frmSettlements because I get a acess violation.

thanx

MerijnB

> When I am in frmSettlements I dont want to allow F5 -> to call again frmSettlements because I get a acess violation

I don't think that will happen since you show the form modal (ShowModal)

henryreynolds

ASKER

How can I prevent calling the form again.

Geert G

put a check and see if the form is of that class or not

procedure TfrmMain.FormKeyUp(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
   if not (Self is TfrmAlphaSearch) and (Key = VK_F3) then
   begin
      Application.CreateForm(TfrmAlphaSearch, frmAlphaSearch);
      try
         frmAlphaSearch.ShowModal();
      finally
         frmAlphaSearch.Free;
      end;
   end;
 
 
   if not (self is TfrmSettlements) and (Key = VK_F5) then
   begin
         Application.CreateForm(TfrmSettlements, frmSettlements);
         try
            frmSettlements.ShowModal();
         finally
            frmSettlements.Free;
         end;
    end;
end;

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ASKER CERTIFIED SOLUTION

reynaldio

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