我哭啊,哪位大神帮我翻译一句VB的代码到C# ？

    Dim i, s

    for i = 1 to Len(str) 

        s = s & (asc(mid(str, i, 1)) xor key) & "," 

    next

    '----------

    Dim t

    t = (DateDiff("s", #1/1/1970#, Now) * 1000) / 100

    s = s & t 

    '----------

    s = s & key & m 

    '----------

    x = Split(str, ",") 

    m = Right(x(Ubound(x)), 1)

    key = Mid(x(Ubound(x)), len(x(Ubound(x)))-3+1, 2)

    'Wscript.Echo "M = " & m

    'Wscript.Echo "Key = " & key

    '----------

    Dim i, s

    for i = lbound(x) to (ubound(x) - 1) 

        s = s & Chr(Int(x(i)) xor key)

    next