服务器端验证可将文件上传大小限制为5mb

Question

我要添加一个自定义验证器，以确保文件上传大小不应大于5MB。

Answer 1

Define the size using the maxRequestLength attribute of the <httpRuntime> tag (within the <system.web> tag ) of web.config file.

ex:

<system.web>
    ...
    <httpRuntime 
      ...
      maxRequestLength="5242880"   //Number of Bytes (5MB)
      ...
    />
   ...
</system.web>

Showing an alert to the user when updating large file

In the file uploading event handler, check for the 'ContentLength' of the 'PostedFile'.

if (FileUpload1.HasFile && FileUpload1.PostedFile.ContentLength > 5242880)
{
   // Relevant error message goes here...
}

It will be useful to refer to the FileUploadClass MSDN page as well.