怎么得到某一年中某一周的范围

option explicit

private type weekinyear
    firstday as date
    lastday as date
end type

private function getdatebyweek（byval intweekinyear as integer) as weekinyear
dim intdaycount as integer '一年中有多少天
dim intweekcount as integer '一年中有多少个星期
dim lngday as long
    if intweekinyear < 1 then exit function
    intdaycount = 365
    if （year（date) mod 4) = 0 then intdaycount = intdaycount + 1 '如果是闰年，则多加一天
    intweekcount = intdaycount \ 7
    if （intdaycount mod 7) <> 0 then intweekcount = intweekcount + 1
    if intweekinyear > intweekcount then exit function
    lngday = clng（cdate（year（date) & "-1-1"))
    getdatebyweek.firstday = lngday + （intweekinyear - 1) * 7
    getdatebyweek.lastday = lngday + （intweekinyear * 7 - 1)
end function

private sub form_load（)
    debug.print getdatebyweek（1).firstday, getdatebyweek（1).lastday
end sub

option explicit

private type weekinyear
    firstday as date
    lastday as date
end type

private function getdatebyweek（byval intweekinyear as integer) as weekinyear
dim intdaycount as integer '一年中有多少天
dim intweekcount as integer '一年中有多少个星期
dim lngday as long
    if intweekinyear < 1 then exit function
    intdaycount = 365
    if （year（date) mod 4) = 0 then intdaycount = intdaycount + 1 '如果是闰年，则多加一天
    intweekcount = intdaycount \ 7
    if （intdaycount mod 7) <> 0 then intweekcount = intweekcount + 1
    if intweekinyear > intweekcount then exit function
    lngday = clng（cdate（year（date) & "-1-1"))
    getdatebyweek.firstday = lngday + （intweekinyear - 1) * 7
    getdatebyweek.lastday = lngday + （intweekinyear * 7 - 1)
end function

private sub form_load（)
    debug.print getdatebyweek（1).firstday, getdatebyweek（1).lastday
end sub

option explicit

private type weekinyear
    firstday as date
    lastday as date
end type

private function getdatebyweek（byval intweekinyear as integer) as weekinyear
dim intdaycount as integer '一年中有多少天
dim intweekcount as integer '一年中有多少个星期
dim lngday as long
    if intweekinyear < 1 then exit function
    intdaycount = 365
    if （year（date) mod 4) = 0 then intdaycount = intdaycount + 1 '如果是闰年，则多加一天
    intweekcount = intdaycount \ 7
    if （intdaycount mod 7) <> 0 then intweekcount = intweekcount + 1
    if intweekinyear > intweekcount then exit function
    lngday = clng（cdate（year（date) & "-1-1"))
    getdatebyweek.firstday = lngday + （intweekinyear - 1) * 7
    getdatebyweek.lastday = lngday + （intweekinyear * 7 - 1)
end function

private sub form_load（)
    debug.print getdatebyweek（1).firstday, getdatebyweek（1).lastday
end sub

option explicit

private sub command1_click（)
    dim y        as long  '年份
    dim w        as long  '第几周
    dim zerodate as date  '这年头一天
    dim enddate  as date  '这年最后一天
    dim zerowd   as long  '头一天是星期几
    
    y = clng（text6.text)  '年份从文本款输入
    w = clng（text7.text)  '第几周也从文本款输入
    zerodate = cdate（cstr（y) & "年1月1日")
    enddate = cdate（cstr（y) & "年12月31日")
    zerowd = weekday（zerodate) - 1
    if zerowd = 0 then zerowd = 7
    
    dim fromday as date
    dim today   as date
    if w = 1 then
        fromday = zerodate
        today = fromday + （7 - zerowd)
    else
        fromday = zerodate + （7 - zerowd) + 1 + （w - 2) * 7
        today = fromday + 6
    end if
    if fromday > enddate then
        msgbox "没有这一周"
    else
        if today > enddate then today = enddate
        msgbox cstr（y) & "年第" & cstr（w) & "周从" & fromday & "到" & today
    end if
end sub