asked on

Double-Click Without Single

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

snehanshu

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

snehanshu

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.

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sftweng

Have you tried changing the double-click timing to a faster setting in Windows -> Control Panel -> Mouse?

tdk_man

ASKER

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