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Solved

dbgrid focus error

Posted on 2008-10-07
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Medium Priority
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Last Modified: 2010-04-21
hi all,

i have this strange error which seems to be a delphi bug. I have a mdi application. Main form has a treeview and a button. mdichild form has a dbgrid. When i run the application i click on the button in main form to open mdi child form. then i click dbgrid in mdi child form. then i click the treeview on the main form. when i want to go back to dbgrid on mdi child form this error comes. the dbgrid wont get focus. so i need to minimize mdi child form or click another component on the form, then i can click on dbgrid. Please see attach code to be clear. I have reported this problem to Quality Central (#67627), and for sure i wont get the answer anytime soon.

I also had this problem when i use delphi 7. But i can solve it simply by adding "PostMessage(Handle, WM_ACTIVATE, WA_INACTIVE, 0);" on FormActive event. But this wont work in delphi 2007.

Please experts help me solve this problem.

Thanks in advance and sorry for my poor english.

Reynaldi
--------------- Main Form .dfm ---------------------------
 
 
object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 419
  ClientWidth = 672
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  FormStyle = fsMDIForm
  OldCreateOrder = False
  Position = poDesktopCenter
  PixelsPerInch = 96
  TextHeight = 13
  object TreeView1: TTreeView
    Left = 0
    Top = 29
    Width = 121
    Height = 390
    Align = alLeft
    Indent = 19
    TabOrder = 0
    Items.NodeData = {
      01050000001B0000000000000000000000FFFFFFFFFFFFFFFF00000000000000
      000131001B0000000000000000000000FFFFFFFFFFFFFFFF0000000000000000
      0132001B0000000000000000000000FFFFFFFFFFFFFFFF000000000000000001
      33001B0000000000000000000000FFFFFFFFFFFFFFFF00000000000000000134
      001B0000000000000000000000FFFFFFFFFFFFFFFF0000000000000000013500}
  end
  object ToolBar1: TToolBar
    Left = 0
    Top = 0
    Width = 672
    Height = 29
    ButtonHeight = 21
    ButtonWidth = 48
    Caption = 'ToolBar1'
    ShowCaptions = True
    TabOrder = 1
    object ToolButton1: TToolButton
      Left = 0
      Top = 0
      Caption = 'Button 1'
      ImageIndex = 0
      OnClick = ToolButton1Click
    end
  end
end
 
 
 
 
 
--------------- Main Form .Pas ---------------------------
 
 
unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ComCtrls, ToolWin;
 
type
  TForm1 = class(TForm)
    TreeView1: TTreeView;
    ToolBar1: TToolBar;
    ToolButton1: TToolButton;
    procedure ToolButton1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
uses
  unit2;
 
{$R *.dfm}
 
procedure TForm1.ToolButton1Click(Sender: TObject);
var
  frm: TForm2;
begin
  frm := TForm2.Create(self);
end;
 
end.
 
 
 
 
 
 
 
--------------------------- mdi child .dfm --------------------------------
 
 
 
object Form2: TForm2
  Left = 0
  Top = 0
  Caption = 'Form2'
  ClientHeight = 216
  ClientWidth = 243
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  FormStyle = fsMDIChild
  OldCreateOrder = False
  Visible = True
  OnClose = FormClose
  OnCreate = FormCreate
  PixelsPerInch = 96
  TextHeight = 13
  object DBGrid1: TDBGrid
    Left = 8
    Top = 40
    Width = 225
    Height = 168
    DataSource = DataSource1
    TabOrder = 0
    TitleFont.Charset = DEFAULT_CHARSET
    TitleFont.Color = clWindowText
    TitleFont.Height = -11
    TitleFont.Name = 'Tahoma'
    TitleFont.Style = []
  end
  object Edit1: TEdit
    Left = 8
    Top = 8
    Width = 121
    Height = 21
    TabOrder = 1
    Text = 'Edit1'
  end
  object ds1: TClientDataSet
    Aggregates = <>
    Params = <>
    Left = 168
    Top = 8
    object ds1field1: TStringField
      FieldName = 'field1'
    end
  end
  object DataSource1: TDataSource
    DataSet = ds1
    Left = 200
    Top = 8
  end
end
 
 
 
 
 
-------------------------- mdi child .pas ---------------------------------------
 
 
unit Unit2;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DB, DBClient, StdCtrls, Grids, DBGrids;
 
type
  TForm2 = class(TForm)
    DBGrid1: TDBGrid;
    Edit1: TEdit;
    ds1: TClientDataSet;
    ds1field1: TStringField;
    DataSource1: TDataSource;
    procedure FormCreate(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
implementation
 
{$R *.dfm}
 
 
 
procedure TForm2.FormCreate(Sender: TObject);
begin
  ds1.CreateDataSet;
  ds1.Open;
  ds1.InsertRecord(['1']);
  ds1.InsertRecord(['2']);
  ds1.InsertRecord(['3']);
  ds1.InsertRecord(['4']);
  ds1.InsertRecord(['5']);
end;
 
 
procedure TForm2.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  action := cafree;
end;
 
 
 
 
end.

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Question by:reynaldio
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10 Comments
 
LVL 13

Expert Comment

by:rfwoolf
ID: 22663148
"this error comes"
>>What is the error?
0
 
LVL 2

Author Comment

by:reynaldio
ID: 22663205
hi rfwoolf,

sorry for not being clear. the problem is that dbgrid wont get focus. i can click any other control on the form, but not dbgrid. this problem only occurs with mdi application.

thanks
0
 
LVL 38

Expert Comment

by:Geert Gruwez
ID: 22666877
set the parent of the child control to the mdi form


procedure TForm1.ToolButton1Click(Sender: TObject);
var
  frm: TForm2;
begin
  frm := TForm2.Create(self);
  frm.parent := Self;
end;

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LVL 2

Author Comment

by:reynaldio
ID: 22668091
hi all,

Geert_Gruwez -> i implemented your code but i get this error "cannot focus a disabled or invinsible windows". What is this?

Thanks
0
 
LVL 38

Expert Comment

by:Geert Gruwez
ID: 22676547
any other code you have added besides the code you posted
for the problematic form ?
0
 
LVL 2

Author Comment

by:reynaldio
ID: 22679399
hi,

no other codes. and i only use standard component. and it only happen with mdi application.
i also had this problem in delphi 7, But i can solve it simply by adding "PostMessage(Handle, WM_ACTIVATE, WA_INACTIVE, 0);" on FormActive event. But this wont work in delphi 2007.

thanks.
0
 
LVL 38

Expert Comment

by:Geert Gruwez
ID: 22684784
if you don't set the parent of the form to the mdiform
then it's not an mdichild form

mdichild means it's a child of an mdiform or the parent must be set

the mdichild behave erratic otherwise

i created a new mdi application with the delphi wizard
no problems (after i added the frm.parent := self)
0
 
LVL 2

Author Comment

by:reynaldio
ID: 22700441
This is how i create mdichild

frm := TMdiChild.Create(Self); --> self is mdi parent
frm.parent := self; --> this raise an error

but if i remove, "frm.parent", the mdi works fine except for the problem i mention above.

Thanks,

Reynaldi
0
 
LVL 11

Accepted Solution

by:
calinutz earned 2000 total points
ID: 25488888
0
 
LVL 2

Author Closing Comment

by:reynaldio
ID: 31503993
Thanks alot, that saved my day
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