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  • Status: Solved
  • Priority: Medium
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how to set property value for all of one kind of TControl


Dear Adviser !

I create a from with several Tedit, several button, serveral DBgrid ....

I want to set Enabled with False for all TEdit.

I know how to get the Tcontrol, but i dont know the kind of control

ChildCotrol : TControl
For i:= 1 to Form.ControlCount do
  ChildControl := form.Controls[i] ;

I wantt to set the value of TexBox, dont need to know object's name

Thank for consider





0
NamCit
Asked:
NamCit
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1 Solution
 
Mohammed NasmanSoftware DeveloperCommented:
Hello

  You can do that using Is operator with the Class name
var
  I : integer;
begin
  for I:= 1 to ControlCount -1 do
  if Controls[I] is TEdit then
    Controls[I].Enabled := False;
end;

Best regards
0
 
NamCitAuthor Commented:

Thanks you  so much.

Please answear me a more question.

1./ How i know the type of variable ?
2./ How i know the whether variable is empty or not. If Empty a number is zero, Empry a string as ''

Because i create a Form to get data return.

I am learning Delphi. A lot of new things


0
 
NamCitAuthor Commented:

Please answear two questions for me again.

Thanks so much

0
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Mohammed NasmanSoftware DeveloperCommented:
Hello

 here are some functions to help you to test the Numeric values


function IsInt(S : string) : Boolean;
begin
  Try
    StrToInt(S);
    Result := True
  Except
    Result := False;
  end;
end;

function IsFloat(S : string) : Boolean;
begin
  Try
    StrToFloat(S);
    Result := True
  Except
    Result := False;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  if Not IsInt(Edit1.Text) then
    ShowMessage('You have to enter Interger Value');

  if Not IsFloat(Edit1.Text) then
    ShowMessage('You have to enter Numeric Value');
end;
==

if you want to test if the Edit1 is empty or not
  if Edit1.Text ='' then
    ShowMessage('You have to enter a Value');  

Best regards
0
 
NamCitAuthor Commented:


IF i set Enabled property. It Is ok.

But if i set Text property. It is wrong.

Please show me the code to set TEdit.Text with ''
0
 
Mohammed NasmanSoftware DeveloperCommented:
use

   TEdit(Controls[I]).Text := '';
0
 
NamCitAuthor Commented:


Delphi doese not support the function to know the kind of variable and the value of variable is empty or not

If not, i will use your comment
0
 
NamCitAuthor Commented:


TEdit(Controls[I]).Text := '';  ?

I try :
  HopDongForm.Controls[I].Text := '';

But not correct

Hearing any news
0
 
Mohammed NasmanSoftware DeveloperCommented:
use
TEdit(HopDongForm.Controls[I]).Text := '';

I saw a mistake by me

start the loop with 0 not 1
for I:= 0 to ControlCount -1 do

delphi doesn't has a function like IsEmpty that found in VB
0
 
NamCitAuthor Commented:

It is ok .

i have solve my problem. Thank you so much.

Mr mnasman, Please explain clearly to me.

Why doest TEDIT mean ? Is is a function ?

I bother you so much today
0
 
Mohammed NasmanSoftware DeveloperCommented:
TEdit is the class of EditBoxs, and we used it to typecasting the control to use the properties like Text, and Edit1 is an object of the Class TEdit

you can use the other classes to like
TCheckBox, TForm, TLabel, and more
0
 
Mohammed NasmanSoftware DeveloperCommented:
NamCit, this is not fair
after all this work, you gave me grade B, it's only 20 points :(
0
 
NamCitAuthor Commented:

sory Mr. Mnasman !

How many points ? I am a new Dp programmer . So i ask a easy question.

Please answear for me this question agai

http://www.experts-exchange.com/jsp/qManageQuestion.jsp?ta=delphi&qid=20321966

so you could hepl me more

you are very kind
0

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