Question

program hang

Asked by: firekiller15

delphi

below is my code
i have a radio button and an edit box
when i select the radio button and curso is in the edit box but i cannot click the button
how to solve

**dfm**
object Form1: TForm1
  Left = 0
  Top = 0
  Width = 347
  Height = 240
  Caption = 'Form1'
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  PixelsPerInch = 96
  TextHeight = 13
  object RadioButton1: TRadioButton
    Left = 16
    Top = 96
    Width = 113
    Height = 17
    Caption = 'RadioButton1'
    TabOrder = 0
  end
  object Edit1: TEdit
    Left = 152
    Top = 88
    Width = 121
    Height = 21
    TabOrder = 1
  end
  object Button1: TButton
    Left = 232
    Top = 168
    Width = 75
    Height = 25
    Caption = 'Button1'
    TabOrder = 2
    OnClick = Button1Click
  end
end
 
**program**
unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;
 
type
  TForm1 = class(TForm)
    RadioButton1: TRadioButton;
    Edit1: TEdit;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
     protected
    procedure UpdateActions(); override;
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.dfm}
 
procedure TForm1.UpdateActions();
const editColors: array[Boolean] of TColor = (cl3DLight, clWhite);
begin
  inherited UpdateActions;
  edit1.Enabled := radiobutton1.Checked;
  edit1.Color := editColors[edit1.Enabled];
  if edit1.Enabled then
  edit1.SetFocus;
end;
 
procedure TForm1.Button1Click(Sender: TObject);
begin
close;
end;
 
end.

                                  
1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:
24:
25:
26:
27:
28:
29:
30:
31:
32:
33:
34:
35:
36:
37:
38:
39:
40:
41:
42:
43:
44:
45:
46:
47:
48:
49:
50:
51:
52:
53:
54:
55:
56:
57:
58:
59:
60:
61:
62:
63:
64:
65:
66:
67:
68:
69:
70:
71:
72:
73:
74:
75:
76:
77:
78:
79:
80:
81:
82:
83:
84:
85:
86:
87:
88:

Select allOpen in new window

This Question has been solved and asker verified All Experts Exchange premium technology solutions are available to subscription members.

Subscribe now for full access to Experts Exchange and get

Instant Access to this Solution

  • Plus...
  • 30 Day FREE access, no risk, no obligation
  • Collaborate with the world's top tech experts
  • Unlimited access to our exclusive solution database
  • Never be left without tech help again

Subscribe Now

Asked On
2008-09-11 at 01:40:37ID23722107
Tags

delphi

Topic

Delphi Programming

Participating Experts
2
Points
250
Comments
17

Trusted by hundreds of thousands everyday for fast, accurate and reliable tech support.

  • "The time we save is the biggest benefit of Experts Exchange to Warner Bros. What could take multiple guys 2 hours or more each to find is accessed in around 15 minutes on Experts Exchange." Mike Kapnisakis, Warner Bros.
  • "Our team likes having a resource that is more secure than just using Google and most experts using this service really know their stuff. It's nice to look here first versus using Google." Dayna Sellner, Lockheed Martin
  • "Anytime that I've been stumped with a problem, 9 out of 10 times Experts Exchange has either the accepted solution or an open discussion of the potential solution to the problem." Kenny Red, eBay Inc.

See what Experts Exchange can do for you.

Got a question?

We've got the answer.

Experts Exchange has been collecting answers to technology questions since 1996…3 million and counting! If you have a question, chances are we already have your answer.

Screenshot of Experts Exchange Knowledgebase

Need individual assistance?

Our experts are ready to help.

If you can't find the exact answer you're looking for, ask our exclusive community of 50,000 experts. You’ll get a personalized answer from a trusted professional.

Screenshot of Experts Exchange Knowledgebase

Want to learn from the best?

Read articles from industry experts.

Thousands of free tech tips, tricks, how-to’s and tutorials are available in our peer reviewed articles section. See for yourself how smart our experts are, no login required.

Screenshot of an Article

Working on a long term project?

Store your work and research.

Save solutions to your questions, answers you’ve discovered through searching plus helpful articles in your personal knowledgebase for easy future access.

Screenshot of Experts Exchange Knowledgebase

Access the answers to your technology questions today.

Subscribe Now

30-day free trial. Register in 60 seconds.

What Makes Experts Exchange Unique?

Members of the expert community talk about why the experience at Experts Exchange is different than what you will find anywhere else.

Trusted by the world's most respected brands.

image of each brand's logo

Faithfully serving IT professionals since 1996.

Experts Exchange Logo

Try it out and discover for yourself.

Subscribe Now

30-day free trial. Register in 60 seconds.

Related Solutions

  1. Radio buttons
    Hi to all of our experts... This is lovely girl, I have a question for you... I have a ONE-to-MANY relationship between 2 tables lets say table1 and table2.. I create a form in Oracle in the following format.. The Master block (Table1) 18 Records (tabular format) The Det...
  2. Radio button and response redirect
    hi guys, i need a little help here as this is my first time using a radio button in ASP. i just need someone to help me, to make an "if-then-else" statement to my code below and add some "response.redirect" code. Please view my code.. html> head> t...
  3. Radio Button
    Hi all.... i am very new to javascript and i am facing this problem. Radio button.... I need to store the the value of the radio button into a variable. my syntax is var expertise=document.surveyform.expertiseradio.selectedIndex var result1=document.surveyform.expertise...
  4. Radio Buttons
    Ok, im trying to validate radio buttons, there are two questions, both need to be answers. At the moment the submit button is button type, if i change it to submit the form is submitted even if the alert boxes apear. i have the following: <script language="JavaScript...

Free Tech Articles

  1. WARNING: 5 Reasons why you should NEVER fix a computer for free.
    It is in our nature to love the puzzle. We are obsessed. The lot of us. We love puzzles. We love the challenge. We thrive on finding the answer. We hate disarray. It bothers us deep in our soul. W...
  2. SCCM OSD Basic troubleshooting
    SCCM 2007 OSD is a fantastic way to deploy operating systems, however, like most things SCCM issues can sometimes be difficult to resolve due to the sheer volume of logs to sift through and the dispe...
  3. Migrate Small Business Server 2003 to Exchange 2010 and Windows 2008 R2
    This guide is intended to provide step by step instructions on how to migrate from Small Business Server 2003 to Windows 2008 R2 with Exchange 2010. For this migration to work you will need the fo...
  4. Create a Win7 Gadget
    This article shows you how to create a simple "Gadget" -- a sort of mini-application supported by Windows 7 and Vista. Gadgets can be dropped anywhere on the desktop to provide instant information, ...
  5. Outlook continually prompting for username and password
    There have been a lot of questions recently regarding Outlook prompting for a username and password whilst using Exchange 2007. There are a few reasons why this would happen and I will try to cover t...
  6. Backup Exchange 2010 Information Store using Windows Backup
    There seems to be quite a lot of confusion around the ability to backup Exchange 2010 using the built in Windows Backup feature. This stems from the omission of this feature prior to Exchange 2007 s...

Cloud Class Webinars

  1. Avoiding Bugs in Microsoft Access
    Alison Balter takes and in-depth look at avoiding bugs in Access. In this webinar you will learn about using the immediate window to debug your applications, invoking the debugger, using breakpoints to troubleshoot, stepping through code, setting the next statement to execute, ...
  2. Top 10 Best New Features in Visio 2010
    Scott Helmers gives live demonstrations of the top 10 new features in Visio 2010. This webinar will teach you how to create compelling diagrams by adding shapes to the page with a single click, linking the shapes in a diagram to data in Excel (or SQL Server, or SharePoint), ...
  3. IT Consultant Business Secrets Revealed
    Michael Munger, Experts Exchange tech pro and IT consultant, pulls back the curtain on his very successful businesses and answers question on every IT consultant and business owner should know about. He shares secrets on what he did to solve the 5 most common problems in IT, ...
  4. Disaster Recovery and Business Continuity
    Quest CTO, Mike Billon, gives an overview of the steps involved in building a dunamic disaster recovery plan. Through case studies and an examination of software/hardware tooles for monitoring and testing, you'll gain a better understandin of where you are, where you want ...
  5. Organize Your Visio Diagrams with Containers and Lists
    Scott Helmers uses cross functional flowcharts, wireframe diagrams, data graphic legends and seating charts to teach you: how to ustilize all three new structured diagram components in Visio 2010, the best practices for organizeing shapes in previous version of Visio, how to organize ...
  6. How to Us Objects, Properties, Events and Methods in Microsoft Access
    Alison Dalter gives an in-depbth look at objects, properties, events and methods in Microsoft Access. In this webinar you will learn about using the object browser, referring to objects, working with properties and methods, working with object variables, understanding the ...

Join the Community

Give a Little. Get a Lot.

Join the community of experts here and help other tech pros by answering question in your area of expertise. You can earn FREE access to all Experts Exchange's premium features and resources.

Join the Community

Answers

 

by: Geert_GruwezPosted on 2008-09-11 at 01:43:18ID: 22447397

remove this from the updateActions

do not change focus in the UpdateActions !

 

by: arashvPosted on 2008-09-11 at 10:20:23ID: 22452213

Hi,
UpdateActions() is called Automatically in the idle time of the form to make all items on the form to some kind of processing their messages and get fresh. when the UpdateActions() is called it kinda locks the form's message Queue and when you call setfocus() of a component, you are putting a new message in that.so it hangs! :)

 

by: firekiller15Posted on 2008-09-11 at 18:10:51ID: 22456422

where should i put my setfocus then

 

by: arashvPosted on 2008-09-11 at 19:02:14ID: 22456584

you know I looked at your code again and I found out that you have overridden the method so it is so simple to solve the problem.just replace your UpdateActions() method with this one:

procedure TForm1.UpdateActions();
const editColors: array[Boolean] of TColor = (cl3DLight, clWhite);
begin
  inherited UpdateActions;
  edit1.Enabled := radiobutton1.Checked;
  edit1.Color := editColors[edit1.Enabled];
  if edit1.Enabled then
    if (Edit1.Tag = 0) then
    begin
      edit1.SetFocus;
      edit1.Tag := 1;
    end
    else
    begin
      Edit1.Tag := 0;
    end;
end;

                                              
1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:

Select allOpen in new window

 

by: firekiller15Posted on 2008-09-11 at 20:26:51ID: 22456916

Do you mind to explan about .Tag (how to use)

 

by: Geert_GruwezPosted on 2008-09-11 at 23:52:08ID: 22457606

procedure TForm1.UpdateActions;
const editColors: array[Boolean] of TColor = (cl3DLight, clWhite);
var OldState: Boolean;
begin
  inherited UpdateActions;
  OldState := Edit1.Enabled;
  Edit1.Enabled := radiobutton1.Checked;
  Edit1.Color := editColors[edit1.Enabled];
  if (OldState <> Edit1.Enabled) and Edit1.Enabled then
    edit1.SetFocus;
end;

                                              
1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:

Select allOpen in new window

 

by: arashvPosted on 2008-09-12 at 05:32:36ID: 22459044

yeah, of course, I see why you didn't get it. It was my fault, I forget a pair of "begin..end". So sorry. The correct code snippet is attached.
I used the "Tag" property as a flag.
The default value of the tag property is 0 (Assuming you didn't change it), so first time the function executes finds the Tag property equal to 0 and if edit1.Enabled = True it calls the setfocus() of Edit1 just for ONCE and then sets the Tag property to 1.
The next time the function is being executed, it checks Edit1.Enabled. If it is True it checks Edit1.Tag and
if it is 0 it sets it to 1 and calls setfocus; otherwise it means that Edit1 Already has the focus so it doesn't call setfocus.(So there won't be infinite calls again and again on the setfocus!)
if Edit1.Enabled is False, then we should reset the tag property.

procedure TForm1.UpdateActions();
const editColors: array[Boolean] of TColor = (cl3DLight, clWhite);
begin
  inherited UpdateActions;
  edit1.Enabled := radiobutton1.Checked;
  edit1.Color := editColors[edit1.Enabled];
  if edit1.Enabled then
  begin //******This one I forgot*******
    if (Edit1.Tag = 0) then
    begin
      edit1.SetFocus;
      edit1.Tag := 1;
    end
  end //******This one I forgot*******
  else
  begin
    Edit1.Tag := 0;
  end;
end;

                                              
1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:

Select allOpen in new window

 

by: Geert_GruwezPosted on 2008-09-12 at 05:33:58ID: 22459049

you only need to set focus if it changed from disabled to enabled ...

 

by: arashvPosted on 2008-09-12 at 05:56:37ID: 22459258

to : Geert_Gruwez , Yeah, just the implementations are different. mine and yours are doin' the same :)

 

by: Geert_GruwezPosted on 2008-09-12 at 06:12:13ID: 22459393

unless the user has put something in the .Tag which he loses with your approach

 

by: arashvPosted on 2008-09-12 at 06:30:42ID: 22459555

Dear Geert_Gruwez I didn't use the tag for no purpose! I used it because It has the ability to extend the code!
Assume you want to set the focus or kill it when a certain event happens, with your code it's not possible without changing and complicating the UpdateActions(), but in my code it's as simple as switching the edit1.tag to 0 or 1 anywhere in the code you want!

 

by: Geert_GruwezPosted on 2008-09-16 at 11:54:40ID: 22491937

have you ever used UpdateActions ?
if so, how would you solve a test for database connectivity with this ?

 

by: Geert_GruwezPosted on 2008-09-16 at 12:02:01ID: 22492034

i'll give you a hint for the datbase of this user:
database connectivity from Delphi to oracle can be tested with this:

function TForm1.IsDBConnected: boolean;
var Qry: TQuery;
begin
  Result := False;
  Qry := TQuery.Create(Self);
  try
    Qry.SQL.Text := 'SELECT SYSDATE FROM DUAL';
    Qry.Open;
    if not Qry.IsEmpty and (Qry.FieldByName('SYSDATE').AsDateTime > Now - 0.1) then Result := True;
    Qry.Close;
  finally
    FreeAndNil(Qry);
  end;
end;

and yes, this is a trick question :)

 

by: Geert_GruwezPosted on 2008-09-16 at 12:02:14ID: 22492040

>>Assume you want to set the focus or kill it
??? i never had to kill a edit or a focus :)  it's never hurt me up to now ...

 

by: arashvPosted on 2008-09-16 at 13:05:13ID: 22492665

>>>>Assume you want to set the focus or kill it
>>??? i never had to kill a edit or a focus :)  it's never hurt me up to now ...

what I meant was If you want to call setfocus() of a component or DefocusControl() of a form(was it so hard to understand "Killing focus"?! It's a very common expression I think!) you need to mess up your UpdateActions function your way!
Ok, if you don't like my method, just ignore it, why are you disrespecting people?

 

by: Geert_GruwezPosted on 2008-09-16 at 15:38:09ID: 22493964

disrespect ? no, just a little humor.
>>if so, how would you solve a test for database connectivity with this ?
you didn't answer this question ... no answer ?

>>with your code it's not possible without changing and complicating the UpdateActions()
the tag can be used for many things but try and leave that up to the developer.
and admit it, writing Edit1.Tag := 0 is a poor way of having to set the focus

 

by: arashvPosted on 2008-09-16 at 15:57:26ID: 22494070

oh I hadn't seen your comment before. I read it and I don't know what's the relation between your question and this topic and what exactly do you want to do? you really want to put a function with a query in UpdateActions() ????? why bother, if you want to lower the performance of the program and the system just call your form's repaint method in onmousemove event!!!!

20120131-EE-VQP-002

3 Ways to Join

30-Day Free Trial

The Experts

98% positive feedback on 31,087 answers since March 2000. angeliii is a Microsoft Most Valuable Professional for his work with MS SQL Server & Develoment.

He has also proven his knowledge of Visual Basic Programming, PHP Scripting and Oracle Databases.

The Experts

97% positive feedback on 10,752 answers since July 2000. lrmoore has more than 18 years experience in the networking industry.

The six-time Mircosoft MVPs specialties include firewalls, virtual private networking, and network management.

Testimonials

"...and excellent source for support... Kind of like having your very own IT dept." Electriciansnet

Testimonials

"I was apprehensive at signing up at first. However... it has already made my life as an IT administrator much easier." JaCrews

Testimonials

"WOW! You guys have great, active, and knowledgeable people on here." moore50

Business Clients

Business Clients

In the Press

"If you’ve got a question... Experts Exchange can supply an answer.”

In the Press

"...an invaluable aid for both IT professionals and those who require tech support."

In the Press

"where IT professionals provide quick answers on just about any topic"

Business Account Plans

Loading Advertisement...