Html 在asp.net中访问服务器端的输入类型文件
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Accessing input type file at server side in asp.net
提问by Ajay
I am using the <input type="file" />tag to upload a file to the server. How do I access the file at the server side and store it at the server? (The file is an image file)
我正在使用<input type="file" />标签将文件上传到服务器。如何在服务器端访问文件并将其存储在服务器上？（该文件是一个图像文件）
The client side code is :
客户端代码是：
<form id="form1" action="PhotoStore.aspx" enctype="multipart/form-data">
<div>
<input type="file" id="file" onchange="preview(this)" />
<input type="submit" />
</div>
</form>
Photostore.aspx.cs has
Photostore.aspx.cs 有
protected void Page_Load(object sender, EventArgs e)
{
int index = 1;
foreach (HttpPostedFile postedFile in Request.Files)
{
int contentLength = postedFile.ContentLength;
string contentType = postedFile.ContentType;
string fileName = postedFile.FileName;
postedFile.SaveAs(@"c:\test\file" + index + ".tmp");
index++;
}
}
I tried uploading a jpg file. Not able to see a saved file. What is going wrong?
我尝试上传一个 jpg 文件。无法查看已保存的文件。出了什么问题？
回答by LukeH
You'll need to add idand runat="server"attributes like this:
你需要添加id和runat="server"属性，就像这样：
<input type="file" id="MyFileUpload" runat="server" />
Then, on the server-side you'll have access to the control's PostedFileproperty, which will give you ContentLength, ContentType, FileName, InputStreamproperties and a SaveAsmethod etc:
然后，在服务器端，您将可以访问控件的PostedFile属性，该属性将为您提供ContentLength、ContentType、FileName、InputStream属性和SaveAs方法等：
int contentLength = MyFileUpload.PostedFile.ContentLength;
string contentType = MyFileUpload.PostedFile.ContentType;
string fileName = MyFileUpload.PostedFile.FileName;
MyFileUpload.PostedFile.Save(@"c:\test.tmp");
Alternatively, you could use Request.Fileswhich gives you a collection of all uploaded files:
或者，您可以使用Request.Files它为您提供所有上传文件的集合：
int index = 1;
foreach (HttpPostedFile postedFile in Request.Files)
{
int contentLength = postedFile.ContentLength;
string contentType = postedFile.ContentType;
string fileName = postedFile.FileName;
postedFile.Save(@"c:\test" + index + ".tmp");
index++;
}
回答by zod
I think the name tag is required on the file input:
我认为文件输入需要名称标签：
<input type="file" name="file" />
Without this, I don't get anything back.
没有这个，我什么也得不到。
Further problems that I had which might be specific to my machine:
我遇到的其他问题可能特定于我的机器：
I get a
我得到一个
Unable to cast object of type 'System.String' to type 'System.Web.HttpPostedFile'.
error at the line
线路错误
foreach (HttpPostedFile postedFile in Request.Files)
so my final code looks like this:
所以我的最终代码如下所示：
for (var i = 0; i < Request.Files.Count; i++)
{
var postedFile = Request.Files[i];
// do something with file here
}
回答by Dimi Takis
Look into the asp:FileUpload control provided by ASP.NET.
查看 ASP.NET 提供的 asp:FileUpload 控件。
回答by Mark Redman
If you dont want to use the FileUpload control in the toolbox, Give your input an ID then use form[id] to access the input field and cast it to HtmlInputFile.
如果您不想使用工具箱中的 FileUpload 控件，请为您的输入指定一个 ID，然后使用 form[id] 访问输入字段并将其转换为 HtmlInputFile。
example here: http://www.codeproject.com/KB/aspnet/fileupload.aspx
回答by Rune Grimstad
If you give the input-tag an id and add the runat="server" attribute then you can access it easily.
First change your input tag: <input type="file" id="FileUpload" runat="server" />
Then add the following to your Page_Load method:
如果你给 input-tag 一个 id 并添加 runat="server" 属性，那么你可以很容易地访问它。
首先更改您的输入标签：<input type="file" id="FileUpload" runat="server" />
然后将以下内容添加到您的 Page_Load 方法中：
if (FileUpload.PostedFile != null)
{
FileUpload.PostedFile.SaveAs(@"some path here");
}
This will write your file to a folder of your choice. You can access the PostedFile object if you need to determine the file type or original file name.
这会将您的文件写入您选择的文件夹。如果需要确定文件类型或原始文件名，可以访问 PostedFile 对象。
