StringGrid - clear range of cells based on a cell value
lazarus / 31-LCL

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GregB · 2012-06-08 02:42

I have a stringgrid with a number of columns, one column has a pickbox
that determines which columns in the row can be edited (this varies
depending on the selection) , what i would like to do is if the user
changes the pickbox selection i need to erase the data in the cells on
that row.

The problem i have is in detecting if the pick changes and where i
need to put the code to clear the cells - clear columns 6 to 11 in the
current row
StringGrid1.clean(6, arow, 11, arow, [gznormal]);

I am very new to Lazarus and Freepascal  but have done a fair bit with
Turbo Pascal many many years ago, so am not even sure if a stringgrid
is the right way to go about this.

One other minor thing i can not seem to work out is if the user enters
invalid data and the error message shows, the stringgrid does not show
the current cell as being focused - does not have the red border
thing.

Thanks for any help.


This is what i have so far ... most of it from googleing
Code: [Select]unit Unit2;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs,
Grids,
  StdCtrls;

type

  { TForm1 }

  TForm1 = class(TForm)
    Button1: TButton;
    StringGrid1: TStringGrid;
    procedure Button1Click(Sender: TObject);
    procedure StringGrid1DrawCell(Sender: TObject; aCol, aRow:
Integer;
      aRect: TRect; aState: TGridDrawState);
    procedure StringGrid1SelectCell(Sender: TObject; aCol, aRow:
Integer;
      var CanSelect: Boolean);
    procedure StringGrid1SelectEditor(Sender: TObject; aCol, aRow:
Integer;
      var Editor: TWinControl);
    procedure StringGrid1SetEditText(Sender: TObject; ACol, ARow:
Integer;
      const Value: string);
  private
    { private declarations }
  public
    { public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.lfm}

{ TForm1 }

procedure TForm1.Button1Click(Sender: TObject);
begin
  StringGrid1.col := 2;
  StringGrid1.row := 4;
  StringGrid1.SetFocus;    // this works !!!!!!!!!!!!!!
  StringGrid1.Cells[1,1] := 'Hi World';
end;

// grey out the cells that are not editable
procedure TForm1.StringGrid1DrawCell(Sender: TObject; aCol, aRow:
Integer;
  aRect: TRect; aState: TGridDrawState);
begin
  if ((StringGrid1.cells[5, aRow] = 'Straight')   and (aCol in
[8,9,10,11])) or
     ((StringGrid1.cells[5, aRow] = 'Transition') and (aCol in
[6,7,11]))                or
     ((StringGrid1.cells[5, aRow] = 'Circ_Curve') and (aCol in
[6,7,8,9,10]))
  then
  begin
     StringGrid1.Canvas.Brush.Color := clBtnFace;      // colour
Button Face
     StringGrid1.Canvas.FillRect(aRect);
  //end
  //else
  //begin
  //  StringGrid1.Canvas.Brush.Color := clWindow;      // window
colour
  //  StringGrid1.Canvas.FillRect(aRect);
  end;
end;


// set which cells can be edited based on the alignment option chosen
procedure TForm1.StringGrid1SelectCell(Sender: TObject; aCol, aRow:
Integer;
  var CanSelect: Boolean);
begin
  if ((StringGrid1.cells[5, aRow] = 'Straight')   and (aCol in
[8,9,10,11]))    or
     ((StringGrid1.cells[5, aRow] = 'Transition') and (aCol in
[6,7,11]))                 or
     ((StringGrid1.cells[5, aRow] = 'Circ_Curve') and (aCol in
[6,7,8,9,10]))
  then
     StringGrid1.options := StringGrid1.options - [goEditing]
  else
     StringGrid1.options := StringGrid1.options + [goEditing];

//  if StringGrid1.cells[aRow, 0] = 'PT' and aCol in [5, 8,9,10,11]
then StringGrid1.options := StringGrid1.options - [goEditing];
//  if StringGrid1.cells[aRow, 0] = 'PT' and aCol in [5, 8,9,10,11]
then StringGrid1.options := StringGrid1.options - [goEditing];
end;


// set the pickbox editor for the alignment column
procedure TForm1.StringGrid1SelectEditor(Sender: TObject; aCol, aRow:
Integer;
  var Editor: TWinControl);
var
  old_alignment : string;
begin
  if aCol = 5 then
  begin
     old_alignment := StringGrid1.cells[acol, arow]; // save the
current value
     Editor := StringGrid1.EditorByStyle(cbsPickList);
     TCustomComboBox(Editor).Items.CommaText :=
'Straight,Transition,Circ_Curve';
     // if the user changes the alignment then we need to clear the
data that was there
     if StringGrid1.cells[acol, arow] <> old_alignment then
     begin
                StringGrid1.Clean(6, arow, 11, arow, [gznormal]);
        old_alignment := '';
     end;
  end;
end;


Procedure ValidateReal(rstr : string; var valid : boolean);
var
  A : double;

begin
  // check for conversion errors
  valid := True;
  if (rstr <> '') then
  try
    A := StrToFloat(rstr);
  except
    valid := False;
  end;
end;



procedure TForm1.StringGrid1SetEditText(Sender: TObject; ACol, ARow:
Integer;
  const Value: string);
Var
  valid : boolean;
  orig_col, orig_row : integer;

begin
  orig_col := aCol;
  orig_row := aRow;

  valid := True;

     Case aCol of
                        0  : { point number - no validation required
};
          1  : { point code - no validation required };
          2  : { kilometrage - real } ValidateReal(Value, valid);
                                        3        : { east };
          4      : { north };
          5      : { alignment parameter};
          6      : { bearing } ;
          7      : { distance } ;
          8      : { Xc }  ;
          9  : { Yc }  ;
          10 : { H }    ;
          11 : { Radius } ;
     end;

     If not(valid) then
     begin
        ShowMessage('Invalid data entered ... ' + Value);
        StringGrid1.Cells[orig_col, orig_row] := '';
        StringGrid1.Col := orig_col;
        StringGrid1.Row := orig_row;
        StringGrid1.SetFocus;
     end;

     StringGrid1.Invalidate;  // this repaints the cells when the
pickbox is used have no idea why
end;


end.



This is the form
Code: [Select]object Form1: TForm1
  Left = 1087
  Height = 502
  Top = 48
  Width = 939
  Caption = 'Form1'
  ClientHeight = 502
  ClientWidth = 939
  LCLVersion = '0.9.30.4'
  object StringGrid1: TStringGrid
    Left = 72
    Height = 200
    Top = 56
    Width = 800
    ColCount = 12
    Options = [goFixedVertLine, goFixedHorzLine, goVertLine,
goHorzLine, goRangeSelect, goEditing, goSmoothScroll]
    RowCount = 6
    TabOrder = 0
    OnDrawCell = StringGrid1DrawCell
    OnSelectCell = StringGrid1SelectCell
    OnValidateEntry = StringGrid1ValidateEntry
    ColWidths = (
      64
      80
      73
      64
      64
      64
      64
      64
      64
      64
      64
      64
    )
    Cells = (
      21
      0
      0
      'Code'
      0
      1
      'PT'
      0
      2
      'TP'
      0
      3
      'TRS'
      0
      4
      'TRS'
      0
      5
      'TP'
      1
      0
      'Point Number'
      2
      0
      'Kilometrage'
      3
      0
      'East'
      4
      0
      'North'
      5
      1
      'Straight'
      5
      2
      'Transition'
      5
      3
      'Circ Curve'
      5
      4
      'Transition'
      5
      5
      'Straight'
      6
      0
      'Bearing'
      7
      0
      'Distance'
      8
      0
      'Xc'
      9
      0
      'Yc'
      10
      0
      'H'
      11
      0
      'Radius'
    )
  end
  object Button1: TButton
    Left = 416
    Height = 25
    Top = 0
    Width = 75
    Caption = 'Button1'
    OnClick = Button1Click
    TabOrder = 1
  end
end

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howardpc · 2012-06-08 18:58

QuoteThe problem i have is in detecting if the pick changes and where
i need to put the code to clear the cells - clear columns 6 to 11 in
the current row
StringGrid1.clean(6, arow, 11, arow, [gznormal]);
One problem is not where to put the clearing code, but the fact that
your OnDrawCell routine overwrites the clearing.

Quotethe stringgrid does not show the current cell as being focused -
does not have the red border thing.
For this you need both stringGrid1.FocusRectVisible = True, and
DrawFocusSelected present in the grid's Options.

----------------------------------------------------------------------
GregB · 2012-06-20 07:59

Thanks

I got it to work by creating a global variable to hold the value and
saved it when GetEditText was called and compared that to the value
when SetEditText finished