如何检查上传的文件格式是否正确？ [英] How do I check if the uploaded file has the right format?

问题描述

我使用c＃和asp.net

我创建了一个网页，在其中输入您的信息以便提交。在我的页面上也有一个文件上传：< asp：FileUpload ID =FileUploadPassfotorunat =server/> - 检查是否有上传的东西。像这样：

pre $ if $（$ File $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ H $％ PostedFile;
using（BinaryReader binaryReader = new BinaryReader（file.InputStream））
{
lehrling.passfoto = binaryReader.ReadBytes（file.ContentLength）;
}
LabelPassfotoError.Visible = false;
}
else
{
LabelPassfotoError.Visible = true;
LabelError.Visible = true;



$ b $ p
$ b

它的作用是：正如我所说的，它检查是否有上传。如果没有上传，ErrorLabel会显示，所以用户知道他忘了上传。

我也想检查，如果上传的文件是图像。为了更清楚我只想接受.jpg / .bmp和.gif。如果错误的格式上传，我想显示我的ErrorLabel以及。

我真的不知道我应该怎么做，你能帮我吗？谢谢

解决方案

  protected void Button1_Click（object sender，EventArgs e）
 {
 string strFileName = Path.GetFileName（FileUpload1.PostedFile.FileName）; 
 string strFileWithoutExt = Path.GetFileNameWithoutExtension（strFileName）; 
 string strExtension = Path.GetExtension（strFileName）; 
 if（strExtension ==.jpg|| strExtension ==.bmp|| strExtension ==.gif）
 {
 string strImageFolder =〜/ YourFilePath / ; 
 if（！Directory.Exists（Server.MapPath（strImageFolder）））
 Directory.CreateDirectory（Server.MapPath（strImageFolder））; 
 string _strPath = Server.MapPath（strImageFolder）+ strFileName; 
 FileUpload1.PostedFile.SaveAs（_strPath）; 
 Label1.Text =上传状态：上传文件。 
} 
 else 
 Label1.Text =上传状态：只允许使用.jpg，.bmp和.gif文件！; 
 
 $ / code> 

希望它的帮助更多....

I work with c# and asp.net

I created a webpage with a web form where you enter your information in order to submit it. There is also a file upload on my page: <asp:FileUpload ID="FileUploadPassfoto" runat="server"/> In my c# code behind i coded a IF-Loop which checks if something got uploaded. Like this:

if (FileUploadPassfoto.HasFile == true)
        {
            HttpPostedFile file = FileUploadPassfoto.PostedFile;
            using (BinaryReader binaryReader = new BinaryReader(file.InputStream))
            {
                lehrling.passfoto = binaryReader.ReadBytes(file.ContentLength);
            }
            LabelPassfotoError.Visible = false;
        }
        else
        {
            LabelPassfotoError.Visible = true;
            LabelError.Visible = true;
        }

What it does is: As i said it checks if something got uploaded. If nothing got uploaded a ErrorLabel will be shown so the user knows he forgot to upload.

What i want to check too, is if the uploaded file is a image. To be more clear i only want to accept .jpg/.bmp and .gif. If a wrong format gets uploaded i want to display my ErrorLabel as well.

I dont really know how i should do this, can you please help me? Thank you

解决方案

    protected void Button1_Click(object sender, EventArgs e)
    {
        string strFileName = Path.GetFileName(FileUpload1.PostedFile.FileName);
        string strFileWithoutExt = Path.GetFileNameWithoutExtension(strFileName);
        string strExtension = Path.GetExtension(strFileName);
        if (strExtension == ".jpg" || strExtension == ".bmp" || strExtension == ".gif")
        {
            string strImageFolder = "~/YourFilePath/";
            if (!Directory.Exists(Server.MapPath(strImageFolder)))
                Directory.CreateDirectory(Server.MapPath(strImageFolder));
            string _strPath = Server.MapPath(strImageFolder) + strFileName;
            FileUpload1.PostedFile.SaveAs(_strPath);
            Label1.Text = "Upload status: File uploaded.";
        }
        else
            Label1.Text = "Upload status: only .jpg,.bmp and .gif file are allowed!";
    }

Hope Its Help You much more....

这篇关于如何检查上传的文件格式是否正确？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！