稻农的无组件上传程序ASP.NET版

上传在中,是非常普遍的一项任务,以前用asp的时候,一直用稻农的无组件上传工具,觉得很好用,现在学asp.net了,却发现没有类似原来稻农的无组件上传程序,因此花了点时间,将稻农的无组件上传程序用vb.net改写了一下,可以编译成dll，在c#或者vb.net等任意asp.net支持的语言中使用，在共享出来,希望能为大家节约点时间,也欢迎提出意见和建议,让他更完善。

option explicit on
option strict on

imports system.io
imports system.data
imports system.web.ui.htmlcontrols.htmlinputcontrol

public class uploadfile

    '-------------------------------------------------------------------
  '欢迎转载，但请保留以下声名
   '说明：文件上传类
    '创建时间：2004-11-18
    '作者：刀尖客 qq:51978456
--------------------------------------------------------------------

    private locorgfilename as string                           '原始文件名
    private locnewfilename as string                           '新文件名
    private locuploaddir as string = ""                        '保存目录 注意：要完整路径
    private locallowoverwrite as boolean = false               '如果保存文件已经存在，是否覆盖
    private locallowextfile as string = "doc,jpg,gif,zip"      '许可格式
    private locallowmaxsize as integer = 3 * 1024 * 1024       '许可大小

    public errmsg as string                                     '返回的错误提示

    public readonly property orgfilename() as string
        get
            return locorgfilename
        end get
    end property

    public property newfilename() as string
        get
            return locnewfilename
        end get
        set(byval strvalue as string)
            locnewfilename = strvalue
        end set
    end property

    public property uploaddir() as string
        get
            return locuploaddir
        end get
        set(byval strvalue as string)
            locuploaddir = strvalue
        end set
    end property

    public property allowoverwrite() as boolean
        get
            return locallowoverwrite
        end get

        set(byval blnvalue as boolean)
            locallowoverwrite = blnvalue
        end set

    end property

    public property allowmaxsize() as integer
        get
            return locallowmaxsize
        end get

        set(byval intvalue as integer)
            locallowmaxsize = intvalue
        end set
    end property

    public property allowextfile() as string
        get
            return locallowextfile
        end get

        set(byval strvalue as string)
            locallowextfile = strvalue
        end set
    end property

    '----------------------------------------------------------------------------------------
    '功能说明：上传文件到服务器
    '参数：file 要上传的文件域 israndom 是否采用随机数文件名,如果为flase，则采用文件原来的名称
    '----------------------------------------------------------------------------------------
    public function upload(byref file as system.web.ui.htmlcontrols.htmlinputfile, optional byval israndom as boolean = true) as boolean
        dim objfile as file
        dim oldfilename as string
        dim strnewfilename as string
        dim strextname as string

        if file.postedfile.contentlength = 0 then
            errmsg = "没有上传文件"
            return false
        end if

        oldfilename = file.postedfile.filename

        strextname = getextname(oldfilename)

        if israndom = true then
            locnewfilename = getrandomfilename(oldfilename, strextname)
            strnewfilename = locnewfilename
        else
            locnewfilename = oldfilename
            strnewfilename = locnewfilename
        end if

        if locuploaddir <> "" then
            if directory.exists(locuploaddir) = false then
                errmsg = "上传目录" & locuploaddir & "不存在"
            else
                if objfile.exists(strnewfilename) and locallowoverwrite = false then
                    errmsg = "对不起，服务器上此文件已经存在!"
                    return false
                else

                    if instr(locallowextfile, strextname) <> 0 then

                        if file.postedfile.contentlength <= locallowmaxsize then

                            try
                                file.postedfile.saveas(locuploaddir & "/" & strnewfilename)
                            catch ex as exception
                                errmsg = ex.message
                                return false
                            end try

                        else
                            errmsg = "对不起，只允许上传小于" & locallowmaxsize & "字节的文件，上传文件超出最大的允许的大小!"
                            return false
                        end if

                    else
                        errmsg = "对不起，只允许上传以下格式的文件" & locallowextfile & "!"
                        return false
                    end if

                end if
            end if

        else
            errmsg = "上传目录未设置"
            return false
        end if

        return true

    end function

    '-----------------------------------------------------------------------------------------
    '功能说明：根据日期和时间得到一个不重复的随机数文件名
    '-----------------------------------------------------------------------------------------
    public function getrandomfilename(byval strfilename as string, byval strextname as string) as string

        dim tempfilename as string
        dim ext as string

        tempfilename = cstr(now())
        tempfilename = replace(tempfilename, "-", "")
        tempfilename = replace(tempfilename, ":", "")
        tempfilename = replace(tempfilename, " ", "")
        tempfilename = tempfilename & getrandomnumber(1, 1000)

        getrandomfilename = tempfilename & strextname

    end function

    '----------------------------------------------------------------------------------------
    '功能说明：获取指定上下限内的随机数
    '-----------------------------------------------------------------------------------------

    public function getrandomnumber(optional byval low as integer = 1, optional byval high as integer = 100) as integer
        dim orandom as system.random

        orandom = new system.random(ctype(system.datetime.now.ticks mod system.int32.maxvalue, integer))
        return orandom.next(low, high + 1)

    end function

    '------------------------------------------------------------------------------------
    '功能说明：根据文件名，得到扩展名
    '------------------------------------------------------------------------------------

    public function getextname(byval strfilename as string) as string
        return right(strfilename, instr(strreverse(strfilename), "."))
    end function

end class