没有,自己写
procedure GetFirstLast(const: theDate: TDate
var FirstDate, LastDate: TDate);
var
Y, M, D: Word;
begin
DecodeDate(theDate, Y, M, D);
FirstDate := EncodeDate(Y, M, 1);
if M = 12 then
begin
Inc(Y);
M := 1;
end else Inc(M);
LastDate := EncodeDate(Y, M, 1) - 1;
end;