Hi all.

Using TCxGrid for a lot of stuff over the years. But recently cutomers want "more" :-)

So I've tried to make some of my apps more user friendly by adding the ability to append records "arrow down" directly in the grid.
This is 90% working as intended and customers are happy.

BUT !
Trying to use "arrow up" to undo the insert gives me all kinds off trouble!
Consider this scenario:

1 table - 1 Primary key column calld ID. And with 2 NOT NULL columns (lets call them C2 and C3).

The grid is created with 2 views - and the grid is, not in grid mode, and it is bound.
- one is grouped by C2 and not showing C3.
- the other one is grouped by C3 and not showing C2.

Trying to append records will leave us to manually insert data into either C2 or C3. I've done that on the dataset "onbeforeinsert". And it works :-)
But when I try to cancel the insert, the grid obviously is in a state where it thinks we should post whatever changes (cause we have made 1 change) there is to the underlying DB.
At this point I would like to send a CANCEL to the dataset (which is in dsinsert mode). But to be able to do this I would have to catch the event before it is posted.

This is where I fail - I cannot find a proper event to fire my cancel statement in!

 Can anyone help me - or atleast concur that there is a problem here.

Kind Regards

Bjarne Rasmussen
Trige & Tang
www.trigetang.dk

PROJECT SOURCE TO TEST THIS :

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, cxStyles, cxCustomData, cxGraphics, cxFilter, cxData, cxDataStorage,
  cxEdit, DB, cxDBData, cxGridCustomTableView, cxGridTableView,
  cxGridDBTableView, dxmdaset, cxGridLevel, cxClasses, cxControls,
  cxGridCustomView, cxGrid, StdCtrls, ExtCtrls;

type
  TForm1 = class(TForm)
    cxGrid1DBTableView1: TcxGridDBTableView;
    cxGrid1Level1: TcxGridLevel;
    cxGrid1: TcxGrid;
    dxMemData1: TdxMemData;
    dxMemData1C1: TIntegerField;
    dxMemData1C2: TIntegerField;
    dxMemData1Tekst: TStringField;
    DataSource1: TDataSource;
    cxGrid1DBTableView1RecId: TcxGridDBColumn;
    cxGrid1DBTableView1C1: TcxGridDBColumn;
    cxGrid1DBTableView1C2: TcxGridDBColumn;
    cxGrid1DBTableView1Tekst: TcxGridDBColumn;
    cxGrid1DBTableView2: TcxGridDBTableView;
    cxGrid1DBTableView2RecId: TcxGridDBColumn;
    cxGrid1DBTableView2C1: TcxGridDBColumn;
    cxGrid1DBTableView2C2: TcxGridDBColumn;
    cxGrid1DBTableView2Tekst: TcxGridDBColumn;
    RadioGroup1: TRadioGroup;
    procedure RadioGroup1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
  dxMemData1.Open;
end;

procedure TForm1.RadioGroup1Click(Sender: TObject);
begin
  case RadioGroup1.ItemIndex of
    0 : cxGrid1Level1.GridView := cxGrid1DBTableView1;
    1 : cxGrid1Level1.GridView := cxGrid1DBTableView2;
  end;
end;

end.
 

object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 591
  ClientWidth = 729
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  OnCreate = FormCreate
  PixelsPerInch = 96
  TextHeight = 13
  object cxGrid1: TcxGrid
    Left = 8
    Top = 80
    Width = 689
    Height = 489
    TabOrder = 0
    object cxGrid1DBTableView1: TcxGridDBTableView
      NavigatorButtons.ConfirmDelete = False
      DataController.DataSource = DataSource1
      DataController.Summary.DefaultGroupSummaryItems = <>
      DataController.Summary.FooterSummaryItems = <>
      DataController.Summary.SummaryGroups = <>
      OptionsData.Appending = True
      OptionsView.GroupByBox = False
      object cxGrid1DBTableView1RecId: TcxGridDBColumn
        DataBinding.FieldName = 'RecId'
        Visible = False
      end
      object cxGrid1DBTableView1C1: TcxGridDBColumn
        DataBinding.FieldName = 'C1'
        Width = 117
      end
      object cxGrid1DBTableView1C2: TcxGridDBColumn
        DataBinding.FieldName = 'C2'
        Visible = False
      end
      object cxGrid1DBTableView1Tekst: TcxGridDBColumn
        DataBinding.FieldName = 'Tekst'
        Width = 391
      end
    end
    object cxGrid1DBTableView2: TcxGridDBTableView
      NavigatorButtons.ConfirmDelete = False
      DataController.DataSource = DataSource1
      DataController.Summary.DefaultGroupSummaryItems = <>
      DataController.Summary.FooterSummaryItems = <>
      DataController.Summary.SummaryGroups = <>
      OptionsData.Appending = True
      OptionsView.GroupByBox = False
      object cxGrid1DBTableView2RecId: TcxGridDBColumn
        DataBinding.FieldName = 'RecId'
        Visible = False
      end
      object cxGrid1DBTableView2C1: TcxGridDBColumn
        DataBinding.FieldName = 'C1'
        Visible = False
      end
      object cxGrid1DBTableView2C2: TcxGridDBColumn
        DataBinding.FieldName = 'C2'
      end
      object cxGrid1DBTableView2Tekst: TcxGridDBColumn
        DataBinding.FieldName = 'Tekst'
      end
    end
    object cxGrid1Level1: TcxGridLevel
      GridView = cxGrid1DBTableView1
    end
  end
  object RadioGroup1: TRadioGroup
    Left = 8
    Top = 9
    Width = 113
    Height = 65
    Caption = 'Select View'
    ItemIndex = 0
    Items.Strings = (
      'View 1'
      'View 2')
    TabOrder = 1
    OnClick = RadioGroup1Click
  end
  object dxMemData1: TdxMemData
    Indexes = <>
    SortOptions = []
    Left = 608
    Top = 32
    object dxMemData1C1: TIntegerField
      FieldName = 'C1'
      Required = True
    end
    object dxMemData1C2: TIntegerField
      FieldName = 'C2'
      Required = True
    end
    object dxMemData1Tekst: TStringField
      FieldName = 'Tekst'
    end
  end
  object DataSource1: TDataSource
    DataSet = dxMemData1
    Left = 568
    Top = 32
  end
end

Well

 I'll tell you all what I've "learned".

The easiest way to capture errors of this kind is to do it on the onposterror of the dataset.
I personally think this is a bad solution - but nevertheless it solves my problem for now :-) 

I would like to see some handles on the grid, so that developers like myself have a better way of catching these situations.

Here is what I've come up with - let me know if anyone has a better idea.

Regards
Bjarne

SOURCE .... replace the old! 

 unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, cxStyles, cxCustomData, cxGraphics, cxFilter, cxData, cxDataStorage,
  cxEdit, DB, cxDBData, cxGridCustomTableView, cxGridTableView,
  cxGridDBTableView, dxmdaset, cxGridLevel, cxClasses, cxControls,
  cxGridCustomView, cxGrid, StdCtrls, ExtCtrls;

type
  TForm1 = class(TForm)
    cxGrid1DBTableView1: TcxGridDBTableView;
    cxGrid1Level1: TcxGridLevel;
    cxGrid1: TcxGrid;
    dxMemData1: TdxMemData;
    dxMemData1C1: TIntegerField;
    dxMemData1C2: TIntegerField;
    dxMemData1Tekst: TStringField;
    DataSource1: TDataSource;
    cxGrid1DBTableView1RecId: TcxGridDBColumn;
    cxGrid1DBTableView1C1: TcxGridDBColumn;
    cxGrid1DBTableView1C2: TcxGridDBColumn;
    cxGrid1DBTableView1Tekst: TcxGridDBColumn;
    cxGrid1DBTableView2: TcxGridDBTableView;
    cxGrid1DBTableView2RecId: TcxGridDBColumn;
    cxGrid1DBTableView2C1: TcxGridDBColumn;
    cxGrid1DBTableView2C2: TcxGridDBColumn;
    cxGrid1DBTableView2Tekst: TcxGridDBColumn;
    RadioGroup1: TRadioGroup;
    procedure RadioGroup1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure NewRec(ADataController: TcxCustomDataController; ARecordIndex: Integer);
    procedure dxMemData1PostError(DataSet: TDataSet; E: EDatabaseError;
      var Action: TDataAction);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.dxMemData1PostError(DataSet: TDataSet; E: EDatabaseError;
  var Action: TDataAction);
var
  tmpStr : String;
begin
  beep;

  tmpStr := 'Missing input : ';
  if dxMemData1C1.IsNull then
    tmpStr := tmpStr +  #13#10 + 'C1 - Input number here.';
  ShowMessage(tmpStr);
  Action := daAbort;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  cxGrid1DBTableView1.DataController.OnNewRecord := NewRec;
  cxGrid1DBTableView2.DataController.OnNewRecord := NewRec;

  dxMemData1.Open;
end;

procedure TForm1.NewRec(ADataController: TcxCustomDataController;
  ARecordIndex: Integer);
begin
  case RadioGroup1.ItemIndex of
    0 : dxMemData1C2.AsInteger := 99;
    1 : dxMemData1C1.AsInteger := 199;
  end;
end;

procedure TForm1.RadioGroup1Click(Sender: TObject);
begin
  case RadioGroup1.ItemIndex of
    0 : begin
          cxGrid1DBTableView2.DataController.DataSource := nil;
          cxGrid1DBTableView1.DataController.DataSource := DataSource1;
          cxGrid1Level1.GridView := cxGrid1DBTableView1;
        end;
    1 : begin
          cxGrid1DBTableView1.DataController.DataSource := nil;
          cxGrid1DBTableView2.DataController.DataSource := DataSource1;
          cxGrid1Level1.GridView := cxGrid1DBTableView2;
        end;
  end;
end;

end.