HOW TO:操作定长字符串

public class ustringclass ustring
    private shared gencoding as system.text.encoding = system.text.encoding.getencoding("gb2312")

    public shared property encoding()property encoding() as system.text.encoding
        get
            return gencoding
        end get
        set(byval value as system.text.encoding)
            gencoding = value
        end set
    end property

    public shared function length()function length(byval s as string) as integer
        return gencoding.getbytecount(s)
    end function

    public shared function padleft()function padleft(byval s as string, byval totalwidth as integer, byval paddingchar as char) as string
        return s.padleft(totalwidth + s.length - length(s), paddingchar)
    end function

    public shared function padleft()function padleft(byval s as string, byval totalwidth as integer) as string
        return s.padleft(totalwidth + s.length - length(s))
    end function

    public shared function padright()function padright(byval s as string, byval totalwidth as integer, byval paddingchar as char) as string
        return s.padright(totalwidth + s.length - length(s), paddingchar)
    end function

    public shared function padright()function padright(byval s as string, byval totalwidth as integer) as string
        return s.padright(totalwidth + s.length - length(s))
    end function

    public shared function substring()function substring(byval line as string, byval index as integer, byval length as integer) as string
        return gencoding.getstring(gencoding.getbytes(line), index, length)
    end function

end class

    private sub toolstripbutton6_click()sub toolstripbutton6_click(byval sender as system.object, byval e as system.eventargs) handles toolstripbutton6.click
        dim tmp as string = "中国china"
        console.writeline(lzmtw.ustring.encoding.encodingname)

        console.writeline(lzmtw.ustring.length(tmp))
        console.writeline(tmp.length)

        console.writeline(tmp.substring(0, 2))
        console.writeline(lzmtw.ustring.substring(tmp, 0, 2))

        console.writeline(new string("*"c, 20))

        console.writeline(lzmtw.ustring.padleft(tmp, 20, "*"c))
        console.writeline(tmp.padleft(20, "*"c))

        console.writeline(lzmtw.ustring.padright(tmp, 20, "*"c))
        console.writeline(tmp.padright(20, "*"c))

        console.writeline(lzmtw.ustring.padleft(tmp, 20))
        console.writeline(tmp.padleft(20))

        console.writeline(lzmtw.ustring.padright(tmp, 20))
        console.writeline(tmp.padright(20))

    end sub