如何檢查上傳文件大小

Question

使用asp.net和C＃上傳過程中檢查文件大小的最佳方法是什麼？我可以通過改變我的web.config上傳大文件而不會有任何問題。當文件上傳超過我允許的最大文件大小時，我的問題就出現了。

我已經研究過使用activex對象，但這不是跨瀏覽器兼容的，也不是解決方案的最佳答案。我需要它是跨瀏覽器兼容的，如果可能的話，並支持IE6（我知道你在想什麼!!但是，我的應用程序用戶中有80％是IE6，這不會很快就會很快改變）。

有沒有發現有同樣的問題嗎？如果是這樣，你是如何解決它的？

Answer 1

我們正在使用NeatUpload來上傳文件。

雖然這樣做的大小檢查後上傳，所以可能不符合您的要求，雖然它可以選擇使用SWFUPLOAD上傳文件和檢查大小等，可以設置的選項，使它不'不要使用這個組件。

由於他們發回回傳處理程序的方式，還可以顯示上傳的進度欄。如果使用內容大小屬性的文件大小超過了所需的大小，您也可以在處理程序的早期拒絕上載。

Answer 2

如果您正在使用System.Web.UI.WebControls.FileUpload控制：

MyFileUploadControl.PostedFile.ContentLength; 

返回發佈文件的大小，以字節爲單位。

Answer 3

這是我在上傳文件時做的，它可能對您有幫助嗎？我會檢查文件大小等。

//did the user upload any file? 
      if (FileUpload1.HasFile) 
      { 
       //Get the name of the file 
       string fileName = FileUpload1.FileName; 

      //Does the file already exist? 
      if (File.Exists(Server.MapPath(ConfigurationManager.AppSettings["fileUploadPath"].ToString() + fileName))) 
      { 
       PanelError.Visible = true; 
       lblError.Text = "A file with the name <b>" + fileName + "</b> already exists on the server."; 
       return; 
      } 

      //Is the file too big to upload? 
      int fileSize = FileUpload1.PostedFile.ContentLength; 
      if (fileSize > (maxFileSize * 1024)) 
      { 
       PanelError.Visible = true; 
       lblError.Text = "Filesize of image is too large. Maximum file size permitted is " + maxFileSize + "KB"; 
       return; 
      } 

      //check that the file is of the permitted file type 
      string fileExtension = Path.GetExtension(fileName); 

      fileExtension = fileExtension.ToLower(); 

      string[] acceptedFileTypes = new string[7]; 
      acceptedFileTypes[0] = ".pdf"; 
      acceptedFileTypes[1] = ".doc"; 
      acceptedFileTypes[2] = ".docx"; 
      acceptedFileTypes[3] = ".jpg"; 
      acceptedFileTypes[4] = ".jpeg"; 
      acceptedFileTypes[5] = ".gif"; 
      acceptedFileTypes[6] = ".png"; 

      bool acceptFile = false; 

      //should we accept the file? 
      for (int i = 0; i <= 6; i++) 
      { 
       if (fileExtension == acceptedFileTypes[i]) 
       { 
        //accept the file, yay! 
        acceptFile = true; 
       } 
      } 

      if (!acceptFile) 
      { 
       PanelError.Visible = true; 
       lblError.Text = "The file you are trying to upload is not a permitted file type!"; 
       return; 
      } 

      //upload the file onto the server 
      FileUpload1.SaveAs(Server.MapPath(ConfigurationManager.AppSettings["fileUploadPath"].ToString() + fileName)); 
     }` 

Answer 4

您可以通過執行以下步驟來做到的Safari和FF只需

<input name='file' type='file'>  

alert(file_field.files[0].fileSize) 

Answer 5

你可以檢查在asp.net：

protected void UploadButton_Click(object sender, EventArgs e) 
{ 
    // Specify the path on the server to 
    // save the uploaded file to. 
    string savePath = @"c:\temp\uploads\"; 

    // Before attempting to save the file, verify 
    // that the FileUpload control contains a file. 
    if (FileUpload1.HasFile) 
    {     
     // Get the size in bytes of the file to upload. 
     int fileSize = FileUpload1.PostedFile.ContentLength; 

     // Allow only files less than 2,100,000 bytes (approximately 2 MB) to be uploaded. 
     if (fileSize < 2100000) 
     { 

      // Append the name of the uploaded file to the path. 
      savePath += Server.HtmlEncode(FileUpload1.FileName); 

      // Call the SaveAs method to save the 
      // uploaded file to the specified path. 
      // This example does not perform all 
      // the necessary error checking.    
      // If a file with the same name 
      // already exists in the specified path, 
      // the uploaded file overwrites it. 
      FileUpload1.SaveAs(savePath); 

      // Notify the user that the file was uploaded successfully. 
      UploadStatusLabel.Text = "Your file was uploaded successfully."; 
     } 
     else 
     { 
      // Notify the user why their file was not uploaded. 
      UploadStatusLabel.Text = "Your file was not uploaded because " + 
            "it exceeds the 2 MB size limit."; 
     } 
    } 
    else 
    { 
     // Notify the user that a file was not uploaded. 
     UploadStatusLabel.Text = "You did not specify a file to upload."; 
    } 
} 

Answer 6

網頁中添加這些行。配置文件。
正常文件上傳大小爲4MB。這裏在system.webmaxRequestLength在KB中提到和在system.webServermaxAllowedContentLength在Bytes中。

<system.web> 
     . 
     . 
     . 
     <httpRuntime executionTimeout="3600" maxRequestLength="102400" useFullyQualifiedRedirectUrl="false" delayNotificationTimeout="60"/> 
    </system.web> 


    <system.webServer> 
     . 
     . 
     . 
     <security> 
      <requestFiltering> 
      <requestLimits maxAllowedContentLength="1024000000" /> 
      <fileExtensions allowUnlisted="true"></fileExtensions> 
      </requestFiltering> 
     </security> 
    </system.webServer> 

，如果你想知道web.config提到maxFile上傳大小使用給定的行.cs頁

System.Configuration.Configuration config = WebConfigurationManager.OpenWebConfiguration("~"); 
    HttpRuntimeSection section = config.GetSection("system.web/httpRuntime") as HttpRuntimeSection; 

    //get Max upload size in MB     
    double maxFileSize = Math.Round(section.MaxRequestLength/1024.0, 1); 

    //get File size in MB 
    double fileSize = (FU_ReplyMail.PostedFile.ContentLength/1024)/1024.0; 

    if (fileSize > 25.0) 
    { 
      ScriptManager.RegisterStartupScript(this.Page, this.GetType(), "Alert", "alert('File Size Exceeded than 25 MB.');", true); 
      return; 
    }