Invalid Cast Exception with Update Panel - asp.net

Question

On Button Click
Protected Sub btnSubmit_Click(sender As Object, e As System.EventArgs) Handles btnSubmit.Click
MsgBox("INSIDE")
If SocialAuthUser.IsLoggedIn Then
Dim accountId As Integer = BLL.getAccIDFromSocialAuthSession
Dim AlbumID As Integer = BLL.createAndReturnNewAlbumId(txtStoryTitle.Text.Trim, "")
Dim URL As String = BLL.getAlbumPicUrl(txtStoryTitle.Text.Trim)
Dim dt As New DataTable
dt.Columns.Add("PictureID")
dt.Columns.Add("AccountID")
dt.Columns.Add("AlbumID")
dt.Columns.Add("URL")
dt.Columns.Add("Thumbnail")
dt.Columns.Add("Description")
dt.Columns.Add("AlbumCover")
dt.Columns.Add("Tags")
dt.Columns.Add("Votes")
dt.Columns.Add("Abused")
dt.Columns.Add("isActive")
Dim Row As DataRow
Dim uniqueFileName As String = ""
If Session("ID") Is Nothing Then
lblMessage.Text = "You don't seem to have uploaded any pictures."
Exit Sub
Else
**Dim FileCount As Integer = Request.Form(Request.Form.Count - 2)**
Dim FileName, TargetName As String
Try
Dim Path As String = Server.MapPath(BLL.getAlbumPicUrl(txtStoryTitle.Text.Trim))
If Not IO.Directory.Exists(Path) Then
IO.Directory.CreateDirectory(Path)
End If
Dim StartIndex As Integer
Dim PicCount As Integer
For i As Integer = 0 To Request.Form.Count - 1
If Request.Form(i).ToLower.Contains("jpg") Or Request.Form(i).ToLower.Contains("gif") Or Request.Form(i).ToLower.Contains("png") Then
StartIndex = i + 1
Exit For
End If
Next
For i As Integer = StartIndex To Request.Form.Count - 4 Step 3
FileName = Request.Form(i)
'## If part here is not kaam ka..but still using it for worst case scenario
If IO.File.Exists(Path & FileName) Then
TargetName = Path & FileName
'MsgBox(TargetName & "--- 1")
Dim j As Integer = 1
While IO.File.Exists(TargetName)
TargetName = Path & IO.Path.GetFileNameWithoutExtension(FileName) & "(" & j & ")" & IO.Path.GetExtension(FileName)
j += 1
End While
Else
uniqueFileName = Guid.NewGuid.ToString & "__" & FileName
TargetName = Path & uniqueFileName
End If
IO.File.Move(Server.MapPath("~/TempUploads/" & Session("ID") & "/" & FileName), TargetName)
PicCount += 1
Row = dt.NewRow()
Row(1) = accountId
Row(2) = AlbumID
Row(3) = URL & uniqueFileName
Row(4) = ""
Row(5) = "No Desc"
Row(6) = "False"
Row(7) = ""
Row(8) = "0"
Row(9) = "0"
Row(10) = "True"
dt.Rows.Add(Row)
Next
If BLL.insertImagesIntoAlbum(dt) Then
lblMessage.Text = PicCount & IIf(PicCount = 1, " Picture", " Pictures") & " Saved!"
lblMessage.ForeColor = Drawing.Color.Black
Dim db As SqlDatabase = Connection.connection
Using cmd As DbCommand = db.GetSqlStringCommand("SELECT PictureID,URL FROM AlbumPictures WHERE AlbumID=#AlbumID AND AccountID=#AccountID")
db.AddInParameter(cmd, "AlbumID", Data.DbType.Int32, AlbumID)
db.AddInParameter(cmd, "AccountID", Data.DbType.Int32, accountId)
Using ds As DataSet = db.ExecuteDataSet(cmd)
If ds.Tables(0).Rows.Count > 0 Then
ListView1.DataSource = ds.Tables(0)
ListView1.DataBind()
Else
lblMessage.Text = "No Such Album Exists."
End If
End Using
End Using
'WebNavigator.GoToResponseRedirect(WebNavigator.URLFor.ReturnUrl("~/Memories/SortImages.aspx?id=" & AlbumID))
Else
'TODO:we'll show some error msg
End If
Catch ex As Exception
MsgBox(ex.Message)
lblMessage.Text = "Oo Poop!!"
End Try
End If
Else
WebNavigator.GoToResponseRedirect(WebNavigator.URLFor.LoginWithReturnUrl("~/Memories/CreateAlbum.aspx"))
Exit Sub
End If
End Sub
The above code works fine.I have added an Update Panel in the page to avoid post back, But when i add the button click as a trigger
<Triggers>
<asp:AsyncPostBackTrigger ControlID="btnSubmit" />
</Triggers>
in the update panel to avoid post back, i get the following error.This happens when i add the button click as a Trigger to the update panel.

Answer 1

The Request.Form returns a NameValueCollection which is accessible by the name of the key or the int indexer. It always returns a String and not an Integer.
Dim FileCount As String = Request.Form(Request.Form.Count - 2)

Answer 2

This is all intuition from the exception message, but on the line
FileCount As Integer = Request.Form(Request.Form.Count - 2)
It looks like Request.Form(Request.Form.Count - 2) is a string, and you're trying trying to assign a it to an integer type.
I don't know what you're trying to do, but the string looks like it contains "true" do you want the following?
FileCount As Integer += Boolean.Parse(Request.Form(Request.Form.Count - 2)) ? 1 : 0;