如何在 TGrid 的单元格中渲染 TBitmap 图像？

Question

I am rendering the content of a database table in a TGrid , which works fine. Now I would like to show an image of a trash can on every row as a button to delete the row. How can this be done?

Answer 1

There are several ways to paint an image in a Grid. In cases, where the images will be loaded at runtime eg from a database, I prefer to use the OnDrawColumnCell event:

procedure TForm1.Grid1DrawColumnCell(Sender: TObject; const Canvas: TCanvas;
  const Column: TColumn; const Bounds: TRectF; const Row: Integer;
  const Value: TValue; const State: TGridDrawStates);
var
  bmp: TBitmap;
begin
  if Column.Name = 'ImageColumn1' then
  begin
    bmp := ImageList1.Bitmap(Bounds.Size, Row mod ImageList1.Count);
    if assigned(bmp) then
    begin
      Grid1.BeginUpdate;
      Canvas.DrawBitmap(bmp, bmp.Bounds, Bounds, 1);
      Grid1.EndUpdate;
    end;
  end;
end;

This example expects an ImageList1 with several preloaded images. It draws all images into the column with the name ImageColumn1 . To take your images from the database, replace the line with the bmp access.

Update at 18-Apr-21:

If you simply want to show a trash icon or eg a status icon, you can put an image list on the form. Add a TImageColumn or TGlyphColumn (eg as column number 2) and fill the image in this event into the cell:

procedure TForm1.Grid1GetValue(Sender: TObject; const ACol, ARow: Integer;
  var Value: TValue);
begin
  if ACol = 2 then
    Value := ImageList1.Bitmap(Bounds.Size, <NumberOfBitmapWithinImageList>);
end;

For a trash icon, you can write your delete action into the following event method:

procedure TForm1.Grid1CellClick(const Column: TColumn; const Row: Integer);
begin
  if Column = ImageColumn1 then
    ShowMessage('Row ' + Row.ToString + ' clicked');
end;

Answer 2

try this code on event onDrawColumnCell

if stgMain.Cells[0, Row] = 'isImage' then begin
  Bounds.Location := PointF(Bounds.Location.X, Bounds.Location.Y + ((Bounds.Height - Bounds.Width) / 2));

  Bounds.Width := Bounds.Width;
  Bounds.Height := Bounds.Width;

  Canvas.Fill.Kind := TBrushKind.Bitmap;
  Canvas.Fill.Bitmap.WrapMode := TWrapMode.TileStretch;

  Canvas.FillRect(Bounds, 0, 0, AllCorners, 1);

  Canvas.Fill.Bitmap.Bitmap := FMain.img.Bitmap(Bounds.Size, 2);
end;