如何验证上传文件的格式

protected void Page_Load(object sender, EventArgs e)

{

if(IsPostBack)

{

Boolean fileOK = false

String path = Server.MapPath("~/UploadedImages/")

if (FileUpload1.HasFile)

{

String fileExtension =

System.IO.Path.GetExtension(FileUpload1.FileName).ToLower()

String[] allowedExtensions =

{".gif", ".png", ".jpeg", ".jpg"}

for (int i = 0i <allowedExtensions.Lengthi++)

{

if (fileExtension == allowedExtensions[i])

{

fileOK = true

}

}

}

if (fileOK)

{

try

{

FileUpload1.PostedFile.SaveAs(path

+ FileUpload1.FileName)

Label1.Text = "File uploaded!"

}

catch (Exception ex)

{

Label1.Text = "File could not be uploaded."

}

}

else

{

Label1.Text = "Cannot accept files of this type."

}

}

}

那只有把这段代码写两次，第一次判断是否合法（不要else），第二次执行上传（不要if），例如：

$kuozhan=array('jpg','gif','doc')

foreach($val['tmp_name'] as $key=>$us){

     foreach($val['name'] as $key=>$ns){

     $arr=pathinfo($val['name'][$key])

     if(!in_array($arr['extension'],$kuozhan)){

     echo " 上传失败，格式错误！"

     return false

     }

}

foreach($val['tmp_name'] as $key=>$us){

     foreach($val['name'] as $key=>$ns){

     $arr=pathinfo($val['name'][$key])

    上传程序

}}

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