FindComponent problem

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October 31st, 2012, 09:56 AM

DLPB

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FindComponent problem

Solved. There was nothing wrong with the code.

I have 4 edit boxes named:

Player1_Edit
Player2_Edit
Player3_Edit
Player4_Edit

I am doing this the short way and using FindComponent (I have other edit boxes which will also need it).

If box is empty on form show, the box should be filled with corrosponding text "Playerx" where x is a number. The first part of this code works fine. It finds the boxes. But it is NOT updating them. Why?

Code:

for i:=1 to 4 do
  if TEdit(FindComponent('Player'+inttostr(i)+'_Edit')).text='' then
  TEdit(FindComponent('Player'+inttostr(i)+'_Edit')).text:='Player'+inttostr(i);

October 31st, 2012, 11:13 AM

majlumbo

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Code:

for i:=1 to 4 do
  if TEdit(FindComponent('Player'+inttostr(i)+'_Edit')).text='' then
  TEdit(FindComponent('Player'+inttostr(i)+'_Edit')).text:='Player'+inttostr(i);

I couldn't find anything obviously wrong with the code so I tested it, and works as expected. The only other possibility is that the edit controls are not empty making the if statement fail, even though it finds the control.

October 31st, 2012, 11:51 AM

DLPB

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I've worked it out. Ugh.

For some reason I am using a TLMDedit not a Tedit. I did make this project a long time ago so... didn't see I had changed it.

The code is fine. I do wish this findcomponent thing gave an error though... it should have done given the boxes are not Tedit.

Anyway thanks!

October 31st, 2012, 02:28 PM

clivew

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Quote:

I do wish this findcomponent thing gave an error though... it should have done given the boxes are not Tedit.

Not if TLMDedit is a descendant of TEdit.
However, in that case one would assume it would work unless TLMDedit overrides the setText method somehow.

Clive

November 1st, 2012, 11:59 AM

emailx45

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Read this before:

http://docs.embarcadero.com/products/rad_studio/delphiAndcpp2009/HelpUpdate2/EN/html/delphivclwin32/Controls_TWinControl.html

http://delphi.about.com/od/vclusing/a/parent_enabled.htm

In essence, the TWinControl is the base class for all Delphi control that can accept focus. For example, TEdit is a descendant of the TWinControl, TLabel is not.

Another way for your needed:

procedure or functions
//////////////////////////////
var
xCmp:TComponent;
For I:= n1 TO nZ do
begin
xCmp:= nil; //for better control of "conditions"
xCmp:= FindComponent(format('Player%d_edit',[i]));
if (xCmp<>nil) and (xCmp is TCustomEdit) then
xCmp.Text := Format('Player%d', [i]);
end;

FindComponent problem

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