TValueListEditor.OnSelectCell Event

Occurs before a cell in the grid is selected.

Pascal

property OnSelectCell: TSelectCellEvent;

C++

__property TSelectCellEvent OnSelectCell;

Description

Write an OnSelectCell event handler to specify whether any particular cell in the grid can be selected. The Col and Row parameters indicate the column and row indexes of the cell that is about to be selected. Set the CanSelect parameter to false to prevent the cell being selected.

C++ Examples:

Copy Code

/*
The following code uses the bitmaps in an image list
component to draw the contents of each cell in a draw grid.
It draws a focus rectangle around the cell that has focus.
goDrawFocusSelect in the DrawGrid Options parameter must be
True to set focus on a cell.  The ImageList Draw method must
be called after DrawFocusRect. The OnSelectCell event handler
must implemented to return true.
*/
void __fastcall TForm1::DrawGrid1DrawCell(
  TObject *Sender, int ACol, int ARow, TRect &Rect, TGridDrawState State)
{
  long index = ARow * DrawGrid1->ColCount + ACol;
  DrawGrid1->Canvas->Brush->Color = clBackground;
  DrawGrid1->Canvas->FillRect(Rect);
  ImageList1->Draw(DrawGrid1->Canvas,Rect.Left,Rect.Top,index);
  if (State.Contains(gdFocused))
  {
    DrawGrid1->Canvas->DrawFocusRect(Rect);
    Label1->Caption = "Cell " + IntToStr(index) + " has the focus.";
  }
  ImageList1->Draw(
    DrawGrid1->Canvas, Rect.Left, Rect.Top, index, True);
}
//---------------------------------------------------------------------------
void __fastcall TForm1::DrawGrid1SelectCell(TObject *Sender, int ACol, int ARow,
      bool &CanSelect)
{
  CanSelect= True;
}

Delphi Examples:

Copy Code

{
The following code uses the bitmaps in an image list
component to draw the contents of each cell in a draw grid.
It draws a focus rectangle around the cell that has focus.
goDrawFocusSelect in the DrawGrid Options parameter must be
True to set focus on a cell.  The ImageList Draw method must
be called after DrawFocusRect. The OnSelectCell event handler
must implemented to return true.
}
procedure TForm1.DrawGrid1DrawCell(Sender: TObject; ACol, ARow: Integer;
  Rect: TRect; State: TGridDrawState);
var
  index: Integer;
begin
  index := ARow * DrawGrid1.ColCount + ACol;
  DrawGrid1.Canvas.Brush.Color := clWhite;
  DrawGrid1.Canvas.FillRect(Rect);
  if (gdFocused in State) then
  begin
    DrawGrid1.Canvas.DrawFocusRect(Rect);
    Label1.Caption:= 'Cell ' + InttoStr(index) + ' has the focus.';
  end;
  ImageList1.Draw(DrawGrid1.Canvas,Rect.Left,Rect.Top,index, True);
end;

procedure TForm1.DrawGrid1SelectCell(Sender: TObject; ACol, ARow: Integer;
  var CanSelect: Boolean);
begin
  CanSelect:= True;
end;

Copy Code

{
The following code ensures that the user cannot select a cell unless it is empty.
} 
procedure TForm1.StringGrid1SelectCell(Sender: TObject; ACol, ARow: Longint; var CanSelect: Boolean);
begin
  CanSelect := (StringGrid1.Cells[ACol, ARow]='')
end;