concatenate filenames - asp.net

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

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 2

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 3

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 4

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

Answer 5

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 6

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 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