delphi - 如何绘制 TStringGrid 的背景

Question

我使用 OnDrawCell 事件自定义绘制 Delphi TStringGrid。单元格覆盖的区域没有问题，但是如何绘制最右一列右侧和最后一行下方的背景？

(编辑)绘画并不是真的必要，我只是想设置背景的颜色。我正在使用 XE2 并研究 VCL 样式。即使在默认绘图中，在字符串网格中设置颜色，接缝也完全没有效果。

TIA

Answer 1

这是我通过google找到的一些代码(它不是我写的，我找不到作者的名字，也许它以某种方式来自StackExchange...)。它定义了 TStringGrid 的后代并实现了新的背景绘制。 (该示例使用位图，但您可以轻松更改它...)

  type
  TStringGrid = class(Grids.TStringGrid)
  private
    FGraphic: TGraphic;
    FStretched: Boolean;
    function BackgroundVisible(var ClipRect: TRect): Boolean;
    procedure PaintBackground;
  protected
    procedure Paint; override;
    procedure Resize; override;
    procedure TopLeftChanged; override;
  public
    property BackgroundGraphic: TGraphic read FGraphic write FGraphic;
    property BackgroundStretched: Boolean read FStretched write FStretched;
  end;

  TForm1 = class(TForm)
    StringGrid: TStringGrid;
    Image: TImage;
    procedure FormCreate(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

{ TStringGrid }

function TStringGrid.BackgroundVisible(var ClipRect: TRect): Boolean;
var
  Info: TGridDrawInfo;
  R: TRect;
begin
  CalcDrawInfo(Info);
  SetRect(ClipRect, 0, 0, Info.Horz.GridBoundary, Info.Vert.GridBoundary);
  R := ClientRect;
  Result := (ClipRect.Right < R.Right) or (ClipRect.Bottom < R.Bottom);
end;

procedure TStringGrid.Paint;
begin
  inherited Paint;
  PaintBackground;
end;

procedure TStringGrid.PaintBackground;
var
  R: TRect;
begin
  if (FGraphic <> nil) and BackgroundVisible(R) then
  begin
    with R do
      ExcludeClipRect(Canvas.Handle, Left, Top, Right, Bottom);
    if FStretched then
      Canvas.StretchDraw(ClientRect, FGraphic)
    else
      Canvas.Draw(0, 0, FGraphic);
  end;
end;

procedure TStringGrid.Resize;
begin
  inherited Resize;
  PaintBackground;
end;

procedure TStringGrid.TopLeftChanged;
begin
  inherited TopLeftChanged;
  PaintBackground;
end;

{ TForm1 }

procedure TForm1.FormCreate(Sender: TObject);
begin
  // Usage: 
  StringGrid.BackgroundGraphic := Image.Picture.Graphic;
  StringGrid.BackgroundStretched := True;
end;