delphi - 如何以编程方式在 Delphi TDateTimePicker 日历中标记日期？

Question

当用户单击 DateTimePicker 并设置为下拉日历时，我希望以某种方式突出显示各种日期(通过我创建的代码选择)——彩色背景、粗体字体、彩色字体，这并不重要。我只想标记某些日期。 ...我该怎么做？

Answer 1

是的，你可以做到这一点。首先，您必须初始化控件:

const
  DTM_GETMCSTYLE = DTM_FIRST + 12;
  DTM_SETMCSTYLE = DTM_FIRST + 11;
...
SendMessage(DateTimePicker1.Handle,
  DTM_SETMCSTYLE,
  0,
  SendMessage(DateTimePicker1.Handle, DTM_GETMCSTYLE, 0, 0) or MCS_DAYSTATE);

(使用 CommCtrl)。

然后您只需响应 MCN_GETDAYSTATE 通知即可。您可以创建自己的 TDateTimePicker 后代，也可以使用“拦截器类”。

type
  TDateTimePicker = class(ComCtrls.TDateTimePicker)    
  protected
    procedure WndProc(var Message: TMessage); override;
  end;

  ...

procedure TDateTimePicker.WndProc(var Message: TMessage);
var
  i: integer;
begin
  inherited;
  case Message.Msg of
    WM_NOTIFY:
      with PNMDayState(Message.LParam)^ do
        if nmhdr.code = MCN_GETDAYSTATE then
        begin
          // The first visible day is SystemTimeToDateTime(stStart);
          // cDayState is probably three, because most often three months are
          // visible at the same time. Of course, the second of these is the
          // 'currently displayed month'.
          // Each month is represented by a DWORD (32-bit unsigned integer)
          // bitfield, where 0 means not bold, and 1 means bold.
          // For instance, the following code will select all days:
          for i := 0 to cDayState - 1 do
            PMonthDayState(Cardinal(prgDayState) + i*sizeof(TMonthDayState))^ := $FFFFFFFF;
        end;
  end;
end;

另一个例子:假设当前显示由三个月组成，并且您只想选择“当前显示的月份”(即中间月份)中的日期。假设您希望从选定的一天开始，每三天选择一次。

然后你想使用位域

Month  Bitfield
0      00000000000000000000000000000000
1      01001001001001001001001001001001
2      00000000000000000000000000000000

哪些是

Month  Bitfield
0      $00000000
1      $49249249
2      $00000000

以十六进制表示。所以你这样做

for i := 0 to cDayState - 1 do
  if i = 1 then
    PMonthDayState(cardinal(prgDayState) + i*sizeof(TMonthDayState))^ := $49249249
  else
    PMonthDayState(cardinal(prgDayState) + i*sizeof(TMonthDayState))^ := $00000000;