RE: [advanced_delphi] Double-clicking row in DBGrid

[Glenn B. Lawler]

Dave,

There is a simpler way to do this with the standard grid if you want to 
avoid subclassing.

All you need to do is track which cell was clicked last. When a DblClick 
event is fired,
The cell which was double-clicked would have to be the last cell that was 
clicked.

To do this, use the MouseDown event, which passes XY mouse coordinates, 
with the
MouseToCell method to determine the Col and Row clicked and save in 
variables.

Here is an example:

const
  MyGridSpecialRow = 5;

var
  MyGridLastColClicked,
  MyGridLastRowClicked: integer;

procedure TMainForm.MyGridMouseDown(Sender: TObject;
  Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
begin
  MyGrid.MouseToCell(X,Y,MyGridLastColClicked,MyGridLastRowClicked);
 {Do whatever else you want to happen in the MouseDown event}
end;

procedure TMainForm.MyGridDblClick(Sender: TObject);
begin
  if MyGridLastRowClicked = MyGridSpecialRow then
    {Do whatever};
end;

Glenn Lawler
www.incodesystems.com

-----Original Message-----
From:   David Smith [SMTP:[EMAIL PROTECTED]
Sent:   Sunday, December 02, 2007 8:51 AM
To:     advanced_delphi@yahoogroups.com
Subject:        RE: [advanced_delphi] Double-clicking row in DBGrid

TMesssage is a custom message event. That is how you obtain the mouse 
coordinates in a non click event. Look at the source code of this event in 
DBGrids.pas and copy its usage of TMessage. Also look up in help about 
TMessage. It's a skill you obviously need to add to your toolbox.

Dave

David Wright <[EMAIL PROTECTED]> wrote:
Thanks...

 I have done very similar code for popup menus, but how  would this 
translate to a double-click event -- that is what is stumping  me...



---------------------------------
 From: advanced_delphi@yahoogroups.com 
 [mailto:[EMAIL PROTECTED] On Behalf Of David  Smith
Sent: Saturday, December 01, 2007 8:03 PM
To:  advanced_delphi@yahoogroups.com
Subject: Re: [advanced_delphi]  Double-clicking row in DBGrid



  As is shown in the source code for DBGrid.pas below. Catch the mouse 
button  up message (which supplies the mouse coordinates) and use with the 
built-in  functions to find out where you are and process accordingly:

procedure  TCustomDBGrid.DefaultHandler(var Msg);
var
  P:  TPopupMenu;
  Cell: TGridCoord;
begin
  inherited  DefaultHandler(Msg);
  if TMessage(Msg).Msg = wm_RButtonUp  then
    with TWMRButtonUp(Msg) do
     begin
      Cell := MouseCoord(XPos,  YPos);
      if (Cell.X < FIndicatorOffset) or  (Cell.Y < 0) then Exit;
      P :=  Columns[RawToDataColumn(Cell.X)].PopupMenu;
       if (P <> nil) and P.AutoPopup then
       begin
         SendCancelMode(nil);
         P.PopupComponent := Self;
        with  ClientToScreen(SmallPointToPoint(Pos))  do
          P.Popup(X,  Y);
        Result :=  1;
      end;
     end;
end;

David Wright <[EMAIL PROTECTED]>  wrote:

   Hi    All,

   I am having a    total mind blank right now...  I know I have done this 
before, but    exactly how escapes me.

   I want to enable    the user to double-click on a row in a DBGrid to 
launch an action.  That    part is easy and works fine.

   What I cannot    remember how to do is ignore double-clicks that occur 
somewhere other than a    row in the table.  For example, if I double-click 
the title bar or the    whitespace below the last row, I do not want to 
launch the    action.

   I know I can get    Mouse Coordinates from the MouseDown event, but how 
do I do this in the Double    Click event?

   Any guidance will    be appreciated,
   Thanks!
   Dave