Delphi：如何在CustomDrawItem中的列表视图中绘制小图标 [英] Delphi: how to draw small icons in List View on CustomDrawItem

问题描述

如何扩展此代码： ListView中的vsReport模式着色的项目和行绘制小图标？

how to extend this code: ListView in vsReport mode colouring of Items and rows. to draw small icons?

为什么我有错误'列表索引超出范围（2）'如果我有3列？

and why do I have the error 'List index out of bounds (2)' if I have 3 columns?

谢谢！

推荐答案

有很多方法可以画这些图标取决于他们来自哪里（文件，资源，系统图标等），并且取决于所有项目是否应该有单个图标，或者每个项目都有自己的图标。无论如何，一般的想法应该从上一个问题的扩展版本的代码中清楚（我也已经修复了超出范围的错误...）：

There are many ways to draw the icons, depending on where they come frome (a file, a resource, a system icon, etc.) and depending on if there should be a single icon for all items or if every item has its own icon. Anyhow, the general idea should be clear from this extended version of the code in the previous question (and I have also fixed the out-of-bounds bug...):

type
  TForm1 = class(TForm)
  ...
  private
    { Private declarations }
    bm: TBitmap;
  ...
  end;

...

implementation

...

procedure TForm1.FormCreate(Sender: TObject);
begin
  bm := TBitmap.Create;
  bm.LoadFromFile('C:\Users\Andreas Rejbrand\Desktop\img.bmp');
end;

procedure TForm1.ListView1DrawItem(Sender: TCustomListView; Item: TListItem;
  Rect: TRect; State: TOwnerDrawState);
var
  i: Integer;
  x1, x2: integer;
  r: TRect;
  S: string;
const
  DT_ALIGN: array[TAlignment] of integer = (DT_LEFT, DT_RIGHT, DT_CENTER);
begin
  if Odd(Item.Index) then
  begin
    Sender.Canvas.Font.Color := clBlack;
    Sender.Canvas.Brush.Color := $F6F6F6;
  end
  else
  begin
    Sender.Canvas.Font.Color := clBlack;
    Sender.Canvas.Brush.Color := clWhite;
  end;
  Sender.Canvas.Brush.Style := bsSolid;
  Sender.Canvas.FillRect(Rect);
  x1 := 0;
  x2 := 0;
  r := Rect;
  Sender.Canvas.Brush.Style := bsClear;
  Sender.Canvas.Draw(3, r.Top + (r.Bottom - r.Top - bm.Height) div 2, bm);
  for i := 0 to ListView1.Columns.Count - 1 do
  begin
    inc(x2, ListView1.Columns[i].Width);
    r.Left := x1;
    r.Right := x2;
    if i = 0 then
    begin
      S := Item.Caption;
      r.Left := bm.Width + 6;
    end
    else
      S := Item.SubItems[i - 1];
    DrawText(Sender.Canvas.Handle,
      S,
      length(S),
      r,
      DT_SINGLELINE or DT_ALIGN[ListView1.Columns[i].Alignment] or
        DT_VCENTER or DT_END_ELLIPSIS);
    x1 := x2;
  end;
end;

屏幕截图http://privat.rejbrand.se/TListViewCustomDrawIcon.png

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