关于ListView的OnCustomDrawXXX事件

显示一个背景图像

 

只填充有效列

procedure TForm1.ListView1CustomDraw(Sender: TCustomListView;

  const ARect: TRect; var DefaultDraw: Boolean);

  function GetHeaderHeight: Integer;

  var

    Header: HWND;           // header window handle

    Pl: TWindowPlacement;   // header window placement

  begin

    // Get header window

    Header := SendMessage(ListView1.Handle, LVM_GETHEADER, 0, 0);

    // Get header window placement

    FillChar(Pl, SizeOf(Pl), 0);

    Pl.length := SizeOf(Pl);

    GetWindowPlacement(Header, @Pl);

    // Calculate header window height

    Result  := Pl.rcNormalPosition.Bottom - Pl.rcNormalPosition.Top;

  end;

var

  BmpXPos, BmpYPos: Integer;  // X and Y position for bitmap

  Bmp: TBitmap;               // Reference to bitmap

  ItemRect: TRect;            // List item bounds rectangle

  TopOffset: Integer;         // Y pos where bmp drawing starts

begin

  // Get top offset where bitmap drawing starts

  if ListView1.Items.Count > 0 then

  begin

    ListView_GetItemRect(ListView1.Handle, 0, ItemRect, LVIR_BOUNDS);

    TopOffset := ListView_GetTopIndex(ListView1.Handle) *

      (ItemRect.Bottom - ItemRect.Top);

  end

  else

    TopOffset := 0;

  BmpYPos := ARect.Top - TopOffset + GetHeaderHeight;

  // Draw the bitmap

  // get reference to bitmap

  Bmp := Image1.Picture.Bitmap;

  // loop until bmp is past bottom of list view

  while BmpYPos < ARect.Bottom do

  begin

    // draw bitmaps across width of display

    BmpXPos := ARect.Left;

    while BmpXPos < ARect.Right do

    begin

      ListView1.Canvas.Draw(BmpXPos, BmpYPos, Bmp);

      Inc(BmpXPos, Bmp.Width);

    end;

    // move to next row

    Inc(BmpYPos, Bmp.Height);

  end;

end;

 

全部填充

// Ensure that the items are drawn transparently

  SetBkMode(ListView1.Canvas.Handle, TRANSPARENT);

  ListView_SetTextBkColor(ListView1.Handle, CLR_NONE);

  ListView_SetBKColor(ListView1.Handle, CLR_NONE);

 

 

隔行换色

 

procedure TForm1.ListView1CustomDrawItem(Sender: TCustomListView;

  Item: TListItem; State: TCustomDrawState;

  var DefaultDraw: Boolean);

const

  cStripe = $CCFFCC;  // colour of alternate list items

begin

  if Odd(Item.Index) then

    // odd list items have green background

    ListView1.Canvas.Brush.Color := cStripe

  else

    // even list items have window colour background

    ListView1.Canvas.Brush.Color := clWindow;

end;

 

 

用不同的颜色显示列

 

procedure TForm1.SetLVColumnColour(ColIdx: Integer);

  // Sets the list view brush colour for the column

const

  // The colours for each list view column

  cRainbow: array[0..3] of TColor = (

    $FFCCCC, $CCFFCC, $CCCCFF, $CCFFFF

  );

begin

  ListView1.Canvas.Brush.Color := cRainBow[ColIdx];

end;

procedure TForm1.ListView1CustomDrawItem(Sender: TCustomListView;

  Item: TListItem; State: TCustomDrawState;

  var DefaultDraw: Boolean);

  // Draw the "Caption" column

begin

  // Set the colour for column 0

  SetLVColumnColour(0);

end;

procedure TForm1.ListView1CustomDrawSubItem(Sender: TCustomListView;

  Item: TListItem; SubItem: Integer; State: TCustomDrawState;

  var DefaultDraw: Boolean);

  // Draw the sub item columns

begin

  // Check if SubItem is 0 and exit (Delphi 4 calls this event 

  // with SubItem = 0, while Delphi 7 starts with SubItem = 1

  if SubItem = 0 then Exit;

  // We set the background colour to the colour required for

  // the column per the SubItem parameter

  SetLVColumnColour(SubItem);

end;

 

 

用不同的字体显示列

 

procedure TForm1.ListView1CustomDrawItem(Sender: TCustomListView;

  Item: TListItem; State: TCustomDrawState;

  var DefaultDraw: Boolean);

  // Set column 0 to use Comic Sans MS italic

begin

  ListView1.Canvas.Font.Name := 'Comic Sans MS';

  ListView1.Canvas.Font.Style := [fsItalic];

end;

procedure TForm1.ListView1CustomDrawSubItem(Sender: TCustomListView;

  Item: TListItem; SubItem: Integer; State: TCustomDrawState;

  var DefaultDraw: Boolean);

begin

  // Ensure SubItem 0 not updated here in Delphi 4

  if SubItem = 0 then Exit;

  if (SubItem = 3) and (Pos('(', Item.SubItems[2]) > 0) then

    // Display negative values in "Amount" column in red

    ListView1.Canvas.Font.Color := clRed

  else

    // Display all other sub item colums in black

    ListView1.Canvas.Font.Color := clBlack;

end;

 

 

显示一个有阴影的列

 

procedure TForm1.ListView1ColumnClick(Sender: TObject;

  Column: TListColumn);

  // Handles column click: updates shaded column

begin

  // Updates the index of the shaded column

  fCurrentCol := Column.Index;

  // Redisplays list view with new column highlighted

  ListView1.Invalidate;

end;

 

private

  fCurrentCol: Integer; // currently selected column 

 

procedure TForm1.ListView1CustomDraw(Sender: TCustomListView;

  const ARect: TRect; var DefaultDraw: Boolean);

  // Displays shading in any area not occupied by list items

var

  ColLeft: Integer; // left edge of selected column

  ColBounds: TRect; // bounds of the selected column

  I: Integer;       // loops thru columns

begin

  // Calculate left side of selected column

  ColLeft := ARect.Left;

  for I := 0 to Pred(fCurrentCol) do

    ColLeft := ColLeft + ListView_GetColumnWidth(ListView1.Handle, I);

  // Calculate bounding rectangle of selected column

  ColBounds := Rect(

    ColLeft,

    ARect.Top,

    ColLeft + ListView_GetColumnWidth(ListView1.Handle, fCurrentCol),

    ARect.Bottom

  );

  // Shade the column

  // other event handlers overwrite this where there are list

  // items but this code ensures shading extends to bottom of

  // list view client rectangle

  ListView1.Canvas.Brush.Color := cShade;

  ListView1.Canvas.FillRect(ColBounds);

end;

 

procedure TForm1.SetLVColumnShading(ColIdx: Integer);

begin

  if fCurrentCol = ColIdx then

    // given column is selected: shade it

    ListView1.Canvas.Brush.Color := cShade

  else

    // given column not shaded: ensure correct background used

    ListView1.Canvas.Brush.Color := ColorToRGB(ListView1.Color);

end;

procedure TForm1.ListView1CustomDrawItem(Sender: TCustomListView;

  Item: TListItem; State: TCustomDrawState;

  var DefaultDraw: Boolean);

  // Shade the first column (index 0) if this is selected

begin

  SetLVColumnShading(0);

end;

procedure TForm1.ListView1CustomDrawSubItem(Sender: TCustomListView;

  Item: TListItem; SubItem: Integer; State: TCustomDrawState;

  var DefaultDraw: Boolean);

  // Shade a sub item column if selected

begin

  if SubItem > 0 then // ensure not column 0 (Delphi 4)

    SetLVColumnShading(SubItem);

end;