Passing Tobject to another form?

Question

I'm writing a touchscreen enabled application in Delphi XE2.

I have a form with TEdits. When I click on them, I call the procedure I've written to show another maximized always on top form with a TTouchkeyboard with a label (for caption) and a TEdit for keyboard input.

My procedure (vkeyboard is my form name with the TTouchkeyboard):

procedure TLogin.showkeyboard(numeric,password: Boolean; 
  caption,value:string;Sender:TObject);
begin
  if numeric then 
    vkeyboard.TouchKeyboard1.Layout := 'NumPad' // make the TTouchkeyboard on the form numeric or alpha
  else 
    vkeyboard.TouchKeyboard1.Layout := 'Standard';
  if password then 
    vkeyboard.input.PasswordChar := '*' //make the TEdit show * or normal characters
  else 
    vkeyboard.input.PasswordChar := #0;
  vkeyboard.title.Caption := caption;
  vkeyboard.input.Text := value;
  vkeyboard.Show;
end;

I'm trying to send Form1.Edit1 object to the form vkeyboard but i don't know how to do it properly!

Why? Because i want to be able to click Done on the input form (vkeyboard) then trace back who was the sender then update the text in the main form edit!

procedure Tvkeyboard.sButton1Click(Sender: TObject);
begin
  (temp as TEdit).Text := input.Text; // send back the text to the right object
  vkeyboard.Hide;
end;

This little part of course didn't work... I think i need to specified that the temp object belong the X form ?

To be clear, i want to trace back who called the procedure or at least be able to specified it in the procedure and then return back the text (from the 2nd form to the main one) to the right TEdit!

Rob Kennedy Rob Kennedy · Accepted Answer · 2012-08-22T02:10:21

You're welcome to pass whatever arguments you want to whatever function you want. If you need to use the passed value in yet another function, you'll need to save it somewhere so the later function can still access it.

Using your example, you appear to have provided a Sender parameter for your showkeyboard function. I assume that's where you're passing a reference to the TEdit control that triggered the keyboard to show. The Tvkeyboard object stored in vkeyboard will need to use that value later, so give a copy of that value to the Tvkeyboard object. Declare a TEdit field:

type
  Tvkeyboard = class(...)
    ...
  public
    EditSender: TEdit;

Then, in showkeyboard, set that field:

vkeyboard.EditSender := Sender;

Finally, use that field when you set the text:

procedure Tvkeyboard.sButton1Click(Sender: TObject);
begin
  EditSender.Text := input.Text; // send back the text to the right object
  Self.Hide;
end;

Since you know it will always be a TEdit control, you can change the type of the Sender parameter in showkeyboard to reflect that specific type:

procedure TLogin.showkeyboard(..., Sender: TEdit);

Passing Tobject to another form?

1 Answers