音樂文件列表也是個不容忽視的問題，自己定個格式當(dāng)然可以，但好在大家熟悉的m3u格式并不復(fù)雜，mediaplayer或winamp都支持它，通用性也好，比起wpl要簡易得多，所以我就來介紹一下m3u格式文件的制作與讀寫
m3u是文本文件，以#extm3u開頭，每個音樂條目占1-2行，當(dāng)存在擴展信息時，首行采用#extinf:開頭，第二行才是文件名；當(dāng)沒有擴展信息時，只是簡單的一行，就是文件名；文件名可包含路徑，也可不包含，不包含時音樂文件應(yīng)該是與m3u文件在同一目錄下。
整個格式就這么簡單，下面是讀取函數(shù)，與保存函數(shù)，讀取時返回的是一個m3u集合，每個集合項目為一首音樂信息的字符串，想獲取這個串的具體內(nèi)容， 可用getm3uinfo函數(shù)返回musicinfo結(jié)構(gòu)。
保存函數(shù)不太完善，需傳入一個m3u集合，因使用集合傳遞m3u字串信息，每個條目只能添加刪除，不能直接修改。若有興趣，可采取類封裝musicinfo結(jié)構(gòu)，并提供修改功能。
private function loadm3ufile(strfilename as string) as collection
dim a() as string, s1 as string, s as string, i as long, fileline() as string
dim blnaddok as boolean, strfilepath as string, coltemp as collection, linenum as long
on error goto fail
set coltemp = new collection
if dir(strfilename) = vbnullstring then goto fail
strfilepath = left$(strfilename, instrrev(strfilename, "/"))
open strfilename for binary as #1
s = input(lof(1), 1)
close
if s = vbnullstring then goto fail
i = instr(1, s, "#extm3u", vbtextcompare)
if i = 0 then goto fail
if i > 1 then s = mid$(s, i)
s = trim$(replace$(s, vbcrlf & vbcrlf, vbcrlf))
fileline = split(s, vbcrlf)
do while linenum <= ubound(fileline)
s = trim$(fileline(linenum))
if s <> vbnullstring then
blnaddok = false
if ucase$(left$(s, 8)) <> "#extinf:" then
if instr(1, s, ":/") = 0 then
s = strfilepath & s
if dir(s, vbnormal or vbhidden or vbreadonly or vbsystem or vbarchive) <> vbnullstring then blnaddok = true
else
if dir(s, vbnormal or vbhidden or vbreadonly or vbsystem or vbarchive) <> vbnullstring then
blnaddok = true
else
s = strfilepath & mid$(s, instrrev(s, "/") + 1)
if dir(s, vbnormal or vbhidden or vbreadonly or vbsystem or vbarchive) <> vbnullstring then blnaddok = true
end if
end if
if blnaddok then
if getmcitype(s) > 0 then
coltemp.add s, s
end if
end if
else
s = mid$(s, 9)
linenum = linenum + 1
s1 = trim$(fileline(linenum))
if s1 <> vbnullstring then
if instr(1, s1, ":/") = 0 then
s1 = strfilepath & s1
if dir(s1, vbnormal or vbhidden or vbreadonly or vbsystem or vbarchive) <> vbnullstring then blnaddok = true
else
if dir(s1, vbnormal or vbhidden or vbreadonly or vbsystem or vbarchive) <> vbnullstring then
blnaddok = true
else
s1 = strfilepath & mid$(s1, instrrev(s1, "/") + 1)
if dir(s1, vbnormal or vbhidden or vbreadonly or vbsystem or vbarchive) <> vbnullstring then blnaddok = true
end if
end if
if blnaddok then
if getmcitype(s1) > 0 then
coltemp.add s & vbcrlf & s1, s1
end if
end if
end if
end if
end if
linenum = linenum + 1
loop
fail:
set loadm3ufile = coltemp
end function
private function savem3u(strfilename as string, colm3ulist as collection) as boolean
dim freeno as long, i as long, a() as string
on error goto fail
if colm3uliste.count > 0 then
freeno = freefile
open strfilename for output as #freeno
print #freeno, "#extm3u"
for i = 1 to colm3uliste.count
a = split(colm3uliste(i), vbcrlf)
if ubound(a) > 0 then
print #freeno, "#extinf:" & colm3uliste(i)
else
print #freeno, colm3uliste(i)
end if
next
close #freeno
savem3u = true
end if
fail:
end function
private function getm3uinfo(m3uitem as string) as musicinfo
dim a() as string, b() as string, tmpinfo as musicinfo
dim i as long, j as long, k as long, s as string
if trim(m3uitem) = vbnullstring then exit function
a = split(m3uitem, vbcrlf)
if ubound(a) > 0 then
j = instr(1, a(0), ",")
k = instr(1, a(0), "-")
if j > 0 and k > 0 then
b = split(a(0), ",")
if val(b(0)) > 0 then tmpinfo.length = val(b(0))
b = split(trim$(b(1)), "-")
if b(0) <> vbnullstring then tmpinfo.artist = trim$(b(0))
if b(1) <> vbnullstring then
tmpinfo.title = trim$(b(1))
else
s = trim$(a(1))
i = instrrev(s, "/")
if i > 0 then
tmpinfo.title = mid$(s, i + 1)
else
tmpinfo.title = s
end if
end if
end if
tmpinfo.filename = a(1)
else
tmpinfo.filename = a(0)
end if
getm3uinfo = tmpinfo
end function
private sub command1_click()
dim tmp as collection, tmpinfo as musicinfo, s as string
set tmp = loadm3ufile(text1.text)
if tmp.count > 0 then
tmpinfo = getm3uinfo(tmp(tmp.count))
s = "文件：" & tmpinfo.filename
s = s & vbcrlf & "歌名：" & tmpinfo.title
s = s & vbcrlf & "歌手：" & tmpinfo.artist
s = s & vbcrlf & "曲長：" & tmpinfo.length & "秒"
msgbox s
end if
end sub
這是一個與上篇相聯(lián)系的代碼，對于一些沒定義的函數(shù)，可在前面的文章中找到
http://blog.csdn.net/homezj/archive/2005/04/15/349005.aspx
