如何在 DBGrid 上绘制垂直居中的内容

Question

已编辑： 我想在 TJvDBGrid（项目的 TDBGrid 的 Jedi 后代）上绘制一个垂直居中的 TIcon 图形和文本。我试图禁用 JvDBGrid 的 DefaultDrawing 方法并覆盖它，但我只能用黑色填充单元格（我认为我的代码不完整，无法进行覆盖）。

现在我succeeded draw the Icon on Cell and the Text remains the same with Default Drawing. How I can center the Icon (vertical and horizontal) and the Text (just vertical ), like this?

这是我的代码：

procedure TFrmXXX.JvDBGridXXXDrawColumnCell(Sender: TObject; const Rect: TRect; DataCol: Integer; Column: TColumn; State: TGridDrawState);
var
  Icon: TIcon;
  fixRect: TRect;
  imgWidth: Integer;
begin
  fixRect := Rect;

  if Column.Index = 0  then //always the first one
  begin
    Icon := GetIcon; //Returns TIcon object
    try
      imgWidth := (Rect.Bottom - Rect.Top);
      fixRect.Right := Rect.Left + imgWidth;
      (Sender as TJvDBGrid).Canvas.StretchDraw(fixRect, Icon);
    finally
      Icon.Free;
    end;
    fixRect := Rect;
    fixRect.Left := fixRect.Left + imgWidth;
  end;

  (Sender as TJvDBGrid).DefaultDrawColumnCell(fixRect, DataCol, Column, State);
end;

Answer 1

经过多次测试，我找到了一种将网上不同教程合并的解决方案。在 DrawColumnCell 事件中，我写了这样的东西：

Canvas.FillRect(Rect); //Fill the cell using current brush.

并且在每个特定的列案例中，我使用了以下方法之一：

Canvas.Draw((Rect.Right - Rect.Left - Icon.Width) div 2 + Rect.Left, (Rect.Bottom - Rect.Top - Icon.Height) div 2 + Rect.Top, Icon); //Draw the graphic centered on cell

Canvas.DrawText(Canvas.Handle, PChar(Column.Field.DisplayText), Length(Column.Field.DisplayText), Rect, DT_VCENTER or DT_CENTER or DT_SINGLELINE or DT_NOPREFIX); //Draw vertical and horizontal centered text

Canvas.DrawText(Canvas.Handle, PChar(Column.Field.DisplayText), Length(Column.Field.DisplayText), Rect, DT_VCENTER or DT_SINGLELINE or DT_NOPREFIX);  //Draw vertical centered and horizontal left justified text

如何在 DBGrid 上绘制垂直居中的内容

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