concatenate filenames

Question

I have the following code in child window which is working but what I want to do is instead of using response.write I want to use label control or to display all the filename like this:

music.pdf, inventory.doc

My Ultimate goal is to pass the values in string (e.g.: "music.pdf, inventory.pdf" ) to the parent window.

How do I do it?

Protected Sub btnUpload_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnUpload.Click
    Try
        '' Get the HttpFileCollection
        Dim hfc As HttpFileCollection = Request.Files
        For i As Integer = 0 To hfc.Count - 1
            Dim hpf As HttpPostedFile = hfc(i)
            If hpf.ContentLength > 0 Then
                hpf.SaveAs(Server.MapPath("/ServerName/DirectoryName") & "\"" & System.IO.Path.GetFileName(hpf.FileName))
                Response.Write("<b>File: </b>" & hpf.FileName & " <b>Size:</b> " & hpf.ContentLength & " <b>Type:</b> " & hpf.ContentType & " Uploaded Successfully! <br/>")
            Else
                Response.Write("Please select a file to upload.")
            End If
        Next i

    Catch ex As Exception

    End Try

End Sub

Answer 1

You can use one of the String.Join() overloads.

Answer 2

Use a string builder to join strings. Strings in .NET are immutable, so Join and any other operators are memory intensive

Comment (not on the question, but I noticed it in your code) Use Path.Combine and any other Path functions. Amazingly easy to forget that they exist and have saved me millions of headaches.

Answer 3

Consider using a <asp:BulletedList>, which is an ASP.NET server control for an unordered list <ul>.

ASPX:

<asp:BulletedList 
   id="uploadedFiles" runat="server"></asp:BulletedList>

Instead of Response.Write() each file, simply:

  Dim displayText as String = string.Format("File: {0}  Size: {1}  Type: {2} Uploaded Successfully", _
          hpf.FileName ,hpf.ContentLength ,hpf.ContentType)

  uploadedFiles.Items.Add(New ListItem(displayText, hpf.FileName ))

Answer 4

This is not the way I would do it but you asked for your code to work with a Label.

ASPX:

<asp:Label id="lblUploadMsg" runat="server" visible="false"></asp:Label>

Code:

Protected Sub btnUpload_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnUpload.Click
    Try
        '' Get the HttpFileCollection
        Dim hfc As HttpFileCollection = Request.Files

        lblUploadMsg.Text = String.empty
        For i As Integer = 0 To hfc.Count - 1
            Dim hpf As HttpPostedFile = hfc(i)
            If hpf.ContentLength > 0 Then
                hpf.SaveAs(Server.MapPath("/ServerName/DirectoryName") & "\"" & System.IO.Path.GetFileName(hpf.FileName))
                lblUploadMsg.Visible = True;                   
                lblUploadMsg.Text +="<b>File: </b>" & hpf.FileName & " <b>Size:</b> " & hpf.ContentLength & " <b>Type:</b> " & hpf.ContentType & " Uploaded Successfully! <br/>"


            Else
                lblUploadMsg.Text="Please select a file to upload."
            End If
        Next i

        ''HTML Encode lblUploadingMsg.Text after

    Catch ex As Exception

    End Try

End Sub

Answer 5

Move your Response.Write outside of the loop over i.

Inside of i loop, keep track using a List<String>. Then, after the loop, use the Response.Write, to write a String.Join over the List.ToArray with a comma.

Answer 6

Add a label control onto the form/control and then instead of using Response.Write, why not use a string builder and append all of the output to that in the loop. Once you have processed all of the files set the Label control's Text property of the string builder ToString method.

Hope this helps

Answer 7

Using a Label control won't honour your <b> tags - what you're looking for here is to use the Literal control. Try something like this:

In your markup:

<asp:literal runat="server" id="UploadedFileInfoLiteral" />

In your code-behind:

Protected Sub btnUpload_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnUpload.Click
Try
    '' Get the HttpFileCollection
    Dim hfc As HttpFileCollection = Request.Files
    Dim FileInfoStringBuilder As System.Text.StringBuilder = New System.Text.StringBuilder
    Dim hpf As HttpPostedFile

    For i As Integer = 0 To hfc.Count - 1
        hpf = hfc(i)
        If hpf.ContentLength > 0 Then
            hpf.SaveAs(Server.MapPath("/ServerName/DirectoryName") & "\"" & System.IO.Path.GetFileName(hpf.FileName))
            FileInfoStringBuilder.Append("<strong>File: </strong>" & hpf.FileName & " <strong>Size:</strong> " & hpf.ContentLength & " <strong>Type:</strong> " & hpf.ContentType & " Uploaded Successfully! <br/>")
        Else
            FileInfoStringBuilder.Append("Please select a file to upload.")
        End If
    Next

    UploadedFileInfoLiteral.Text = FileInfoStringBuilder.ToString()

Catch ex As Exception

End Try

End Sub