Dynamic Folder Names with AjaxFileUpload

Question

I'm attempting to replace the upload /download pages of our very old ASP classic web site with a web forms app. Keeping as much of the back end stuff the same is important as there is code (mostly VBA in Word, Excel and Outlook) in our daily operation that uses the uploaded files.

I've managed to get things working with a login page that uses our existing database and redirects to the upload page that contains the AjaxFileUpload control.

My problem is that each client has a folder to which their files are uploaded and I can't find a way to dynamically change the folder in the AjaxFileUpload's _UploadComplete event. I've tried setting a session variable with the client ID on the login page, the value of which I can get in the Page_Load event of the upload page but is inaccessible in the AjaxFileUpload's code-behind event procedures _UploadComplete and _UploadCompleteAll. I've tried the same idea by setting an invisible label with the client ID in the Page_Load event, but again the label seems inaccessible in the AjaxFileUpload event procedures.

There are also other controls on the page I'll eventually need to access in this way after the upload, like the text box with the name of the person who uploaded. I suspect the inaccessibility of the session variables and label text from the AjaxFileUpload event procedures may be a security thing. Though being completely new to any web dev I very well could be missing something simple.

Thanks for any help,
Ken

Answer 1

You can certainly use code to get/determine the logon, or use session() code in the 3 AjaxToolKit file uploader events.

The only issue to keep in mind, since the upload is now ajax, then controls and values on the page of course cannot be used, since the web page is not being posted back to the server when those upload events are completed.

So, nothing should prevent use of say session() in those events.

I would suggest that you on the page load event (with the AJ fileuploader), you setup some session value in the page load event that sets the users folder in question.

Hence, say some code like this on page load:

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        If Not IsPostBack Then
            Session("UserName") = "Albert" ' testing
            Session("UpLoadFolder") = Server.MapPath("~/UpLoadFiles/Albert") ' testing
            LoadGrid()
            myfiles.Visible = False
            myupload.Visible = True
        End If
    End Sub
    Sub LoadGrid()
        GVFiles.DataSource = MyRst("SELECT * FROM MyFiles ORDER BY UpLoadDate")
        GVFiles.DataBind()
    End Sub
    Protected Sub AjaxFileUpload1_UploadComplete(sender As Object, e As AjaxControlToolkit.AjaxFileUploadEventArgs)
        ' save file to UpLoadFiles folder
        Dim strF As String = Session("UpLoadFolder") & e.FileName
        AjaxFileUpload1.SaveAs(strF)
        ' add this row to database.
        Using conn As New SqlConnection(My.Settings.TEST4)
            Using cmdSQL As New SqlCommand("INSERT INTO MyFiles 
                                           (UserName, FileName, SaveFilePath, UpLoadDate)
                                            VALUES (@User, @FileName, @FPath, @UpLoadDate)", conn)
                cmdSQL.Parameters.Add("@User", SqlDbType.NVarChar).Value = Session("UserName")
                cmdSQL.Parameters.Add("@FileName", SqlDbType.NVarChar).Value = e.FileName
                cmdSQL.Parameters.Add("@FPath", SqlDbType.NVarChar).Value = strF
                cmdSQL.Parameters.Add("@UpLoadDate", SqlDbType.DateTime).Value = DateTime.Now
                conn.Open()
                cmdSQL.ExecuteNonQuery()
            End Using
        End Using
    End Sub

So, as above shows, use of session() is permitted in such upload events.

The above thus results in this:

So, keep in mind that the ajaxfile upload events:

They can NOT see nor use textboxes or controls on the page - the page does not have a post back, and thus you should consider the 3 server events as like a static method.

The 3 events can use session, but the events can NOT use ViewState, since once again, that is client side browser side information - not available in the 3 events for the AjaxFileUpLoader.

After all events are completed, the page is not posted back, and OFTEN I do want extra information such as user comments and other information entered by the user on that given page.

Hence, I often add a final button on the page, hide the button, and have the "final" upload ALL event trigger this button, and thus the result is a final whole page post-back that occures AFTER all the files been upload. For example, in above after all files are done uploading, note how I switched my button/tab to show the uploaded files.

This final code is triggered using JavaScript (jQuery in this example).

hence this:

        <h4>Select Files to upload</h4>
        <br />
        <ajaxToolkit:AjaxFileUpload ID="AjaxFileUpload1" runat="server"
            OnUploadComplete="AjaxFileUpload1_UploadComplete"
            OnClientUploadCompleteAll="alldone" />
    </div>

    <asp:Button ID="cmdAllDone" runat="server" Text="Hidden all done upload Button"
        OnClick="cmdAllDone_Click" ClientIDMode="Static" Style="display: none" />


    <script>

        function alldone() {

            $('#cmdAllDone').click()
        }

    </script>

So note how I added a client side JavaScript event to the AjaxFileUpLoad, and it runs the client side JavaScript routine called "alldone".

And "all done" simply clicks the button I placed on the page. this results in a full page post back, and thus my code behind is free to do some final additional work, or in this case, toggle the div that shows all files uploaded.

Hence the cmdAllDone_Click runs after all files are upload. This code:

    Protected Sub cmdAllDone_Click(sender As Object, e As EventArgs)

        myfiles.Visible = True
        myupload.Visible = False

        LoadGrid()  ' re-load re-fresh the GridView of files
        MyTabs.SelectedIndex = 1

    End Sub

So, that final button click is really just a FYI as to how you can have some server side code run, and have a "often" needed post-back after all files been uploaded.

However, the AJ FileUpLoad most certainly does allow use of session(). However, use of Viewstate(), or use of controls from the page are not available and can't be used.

Answer 2

Hi @Ken Krugh,

My problem is that each client has a folder to which their files are uploaded and I can't find a way to dynamically change the folder in the AjaxFileUpload's _UploadComplete event.

You didn't provide your code, so we don't know why it doesn't work.

Perhaps you can try the following method.

  protected void Page_Load(object sender, EventArgs e)
  {
      Session["path"] = @"C:\";
  }
  protected void AjaxFileUpload1_UploadComplete(object sender, AjaxControlToolkit.AjaxFileUploadEventArgs e)
  {
      var path = Session["path"] + e.FileName;
      AjaxFileUpload1.SaveAs(path);
      //  AjaxFileUpload1.SaveAs(@"C:\" + e.FileName + "");   
  }

 <asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>
 <ajaxToolkit:AjaxFileUpload ID="AjaxFileUpload1" runat="server" OnUploadComplete="AjaxFileUpload1_UploadComplete" />

Best regards,
Lan Huang

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