Solved

Double-Click Without Single

Posted on 2003-11-26
5
356 Views
Last Modified: 2010-04-05
Probably a very easy answer to this one...

I want to do one thing if I click on my memo and another if I double click on it, so I'm using the OnClick and OnDblClick events.

But, it doesn't matter how fast I double click, it only triggers the OnClick event. Any way of stopping this happening?

TDK_Man
0
Comment
Question by:tdk_man
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
5 Comments
 
LVL 5

Expert Comment

by:snehanshu
ID: 9829663
Well, I thought there would be better solutions than what I could think of, but I couldn't find any in a quick search, so here goes a crude method:

Wait (Sleep) for some time in the onclick event and then see if DoubleClick was done. If not process the single click.
Code:

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Memo1: TMemo;
    procedure Memo1Click(Sender: TObject);
    procedure Memo1DblClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  IsDouble: Boolean;

implementation

{$R *.dfm}

procedure TForm1.Memo1Click(Sender: TObject);
begin
 IsDouble := False;
 Sleep(100);
 Application.ProcessMessages;
 If Not ISDouble then
 begin
 //single click handling routine here
   showmessage('Single');
 End;
end;

procedure TForm1.Memo1DblClick(Sender: TObject);
begin
  showmessage('Double');
  IsDouble := True;
end;

end.


HTH,
...Shu
0
 
LVL 5

Expert Comment

by:snehanshu
ID: 9829744
Here's code that reads the doubleclick interval from the registry and sleeps for that amount of time. I am not a TRegistry expert, but this does the work for me :)

Cheers!
...Shu

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, Registry;

type
  TForm1 = class(TForm)
    Memo1: TMemo;
    procedure Memo1Click(Sender: TObject);
    procedure Memo1DblClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  IsDouble: Boolean;

implementation

{$R *.dfm}

procedure TForm1.Memo1Click(Sender: TObject);
Var
  MyReg: TRegistry;
  MyInterval : Integer;
begin

 try
   begin
     MyReg := TRegistry.Create(KEY_READ);
     MyReg.RootKey := HKEY_CURRENT_USER;
     MyReg.OpenKey('Control Panel\Mouse',False);
     MyInterval := StrToIntDef(MyReg.ReadString('DoubleClickSpeed'), 250);
   end
 except
   begin
     MyInterval := 250;//default mouse dblclick interval
   end
 end;
 if assigned(MyReg) then
   MyReg.Free;

 IsDouble := False;
 Sleep(MyInterval);
 Application.ProcessMessages;
 If Not ISDouble then
 begin
 //single click handling routine here
   showmessage('Single');
 End;
end;

procedure TForm1.Memo1DblClick(Sender: TObject);
begin
  showmessage('Double');
  IsDouble := True;
end;

end.
0
 
LVL 9

Accepted Solution

by:
mocarts earned 100 total points
ID: 9830447
hi, TDK_man
Shu is right about main idea, but there is a way for shorter code (and easier to support):

procedure TForm1.Memo1Click(Sender: TObject);
begin
  Memo1.Lines.Add('Click');
  // call windows api function to retrieve system setting for double click time
  // this setting depends on user preferences - by default there will be very slow response time for Click
  // but you can tune that by subtracting some variable (programm setting) value from function result
  Timer1.Interval := GetDoubleClickTime;
  Timer1.Enabled := True;
end;

procedure TForm1.Memo1DblClick(Sender: TObject);
begin
  Timer1.Enabled := False;
  Memo1.Lines.Add('DblClick');
  // your OnDblClick code here
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
  Timer1.Enabled := False;
  Memo1.Lines.Add('Click-Timer');
  // your OnClick code here
end;

wbr, mo.
0
 
LVL 7

Expert Comment

by:sftweng
ID: 9832708
Have you tried changing the double-click timing to a faster setting in Windows -> Control Panel -> Mouse?
0
 
LVL 1

Author Comment

by:tdk_man
ID: 9839076
Sorry for the delay in getting back - I had a power cut and my UPS failed. I ended up having to re-install Windows and all my software.

Will check out all the suggestions (thanks for them) this weekend and get back...

TDK_Man
0

Featured Post

On Demand Webinar: Networking for the Cloud Era

Did you know SD-WANs can improve network connectivity? Check out this webinar to learn how an SD-WAN simplified, one-click tool can help you migrate and manage data in the cloud.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Creating an auto free TStringList The TStringList is a basic and frequently used object in Delphi. On many occasions, you may want to create a temporary list, process some items in the list and be done with the list. In such cases, you have to…
Hello everybody This Article will show you how to validate number with TEdit control, What's the TEdit control? TEdit is a standard Windows edit control on a form, it allows to user to write, read and copy/paste single line of text. Usua…
Monitoring a network: why having a policy is the best policy? Michael Kulchisky, MCSE, MCSA, MCP, VTSP, VSP, CCSP outlines the enormous benefits of having a policy-based approach when monitoring medium and large networks. Software utilized in this v…
This is my first video review of Microsoft Bookings, I will be doing a part two with a bit more information, but wanted to get this out to you folks.
Suggested Courses
Course of the Month3 days, 19 hours left to enroll

630 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question