How to correctly use the ASP NET FileUpload control

Question

I m trying to use the FileUpload control in ASP NET  Here s my current namespace setup   using System  using System IO  using System Collections Generic  using System Linq  using System Text   using System Web  using System Web UI  using System Web UI WebControls  using System Web UI WebControls WebParts    And within my class  I m just using   FileUpload fileUpload   new FileUpload      However  none of the attributes that are normally part of FileUpload seem to be available    such as  HasFile  I m attempting to make the Button click  method in the code behind  I have noticed that most of the usage of  HasFile is in the code in front  however it was my understanding that this shouldn t matter   Does anyone know why

User · Answer

My solution in code behind was   System Web UI WebControls FileUpload fileUpload    I don t know why  but when you are using FileUpload without System Web UI WebControls it is referencing to YourProject FileUpload not System Web UI WebControls FileUpload

User · Answer

Instead of instantiating the FileUpload in your code behind file  just declare it in your markup file   aspx file     lt asp FileUpload ID  fileUpload  runat  server    gt    Then you will be able to access all of the properties of the control  such as HasFile

User · Answer

ASP NET controls should rather be placed in aspx markup file  That is the preferred way of working with them  So add FileUpload control to your page  Make sure it has all required attributes including ID and runat    lt asp FileUpload ID  FileUpload1  runat  server    gt    Instance of FileUpload1 will be automatically created in auto-generated updated   designer cs file which is a partial class for your page  You usually do not have to care about what s in it  just assume that any control on an aspx page is automatically instantiated   Add a button that will do the post back    lt asp Button ID  Button1  runat  server  Text  Button  onclick  Button1 Click    gt    Then go to your   aspx cs file where you have your code and add button click handler  In C  it looks like this   protected void Button1 Click object sender  EventArgs e      if  this FileUpload1 HasFile          this FileUpload1 SaveAs  c       this FileUpload1 FileName           And that s it  All should work as expected

User · Answer

Adding a FileUpload control from the code behind should work just fine  where the HasFile property should be available  for instance in your Click event      If the properties don t appear to be available  either as a compiler error or via intellisense   you probably are referencing a different variable than you think you are

User · Answer

I have noticed that when intellisence doesn t work for an object there is usually an error somewhere in the class above line you are working on   The other option is that you didn t instantiated the FileUpload object as an instance variable   make sure the code   FileUpload fileUpload   new FileUpload      is not inside a function in your code behind

User · Answer

Old Question  but still  if it might help someone  here is complete sample  lt form id  quot form1 quot  runat  quot server quot  gt       lt div gt           lt asp FileUpload ID  quot FileUpload1 quot  runat  quot server quot    gt  lt br  gt           lt asp Button ID  quot Button1 quot  runat  quot server quot  Text  quot Upload File quot  OnClick  quot UploadFile quot    gt  lt br  gt           lt asp Label ID  quot Label1 quot  runat  quot server quot  Text  quot  quot  gt  lt  asp Label gt       lt  div gt   lt  form gt   In your Code-behind  C  code to grab file and save it in Directory protected void UploadFile object sender  EventArgs e                  folder path to save uploaded file         string folderPath   Server MapPath  quot   Upload  quot               Check whether Directory  Folder  exists  although we have created  if it si not created this code will check         if   Directory Exists folderPath                           If folder does not exists  Create it              Directory CreateDirectory folderPath                       save file in the specified folder and path         FileUpload1 SaveAs folderPath   Path GetFileName FileUpload1 FileName               once file is uploaded show message to user in label control         Label1 Text   Path GetFileName FileUpload1 FileName     quot  has been uploaded  quot          Source  File Upload in ASP NET  Web-Forms Upload control example

[c#] How to correctly use the ASP.NET FileUpload control

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