VB.NET Drag Drop Error

Hi All... I am using the code below to drag&drop files between listboxes. For some reason I am now getting an exception 'Value Cannot be Null. Parameter Name: item'. When I use: 'If result = DialogResult.Yes' and attempt to SPLIT the job (which is only renaming the file and moving a copy) this is where the error happens and I am not certain why. The file does move, but does not get to the append to file portion. I am stuck here on this as I don't really understand the error.

*** EDIT: Just realized the .Tag property was incorrect in that portion of the code. I still think this needs more efficiency added. Please feel free to add any comments.

Code:

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Private Sub ListBoxes_DragDrop(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles ListBox6.DragDrop, ListBox5.DragDrop, ListBox4.DragDrop, ListBox3.DragDrop, ListBox2.DragDrop, ListBox1.DragDrop, ListBox7.DragDrop


        Try
            If e.Data.GetDataPresent(GetType(FileInfo)) Then

                With DirectCast(sender, ListBox)

                    Dim NewFile As String
                    Dim fileDropped As FileInfo = DirectCast(e.Data.GetData(GetType(FileInfo)), FileInfo)
                    Dim FileToMove As String = fileDropped.FullName
                    Dim MoveLocation As String = strPath & "\" & CStr(.Tag) & "\" & fileDropped.Name


                    If sender IsNot ListBox7 OrElse (sender Is ListBox7 AndAlso .Items.Count = 0) Then
                        blocked = False
                    Else
                        MsgBox("Only one job at a time can be running!" & vbCrLf & vbCrLf & "Move first job from Queue before continuing.", vbCritical, "")
                        blocked = True
                    End If


                    If CStr(.Tag) = "SMT-Complete" Then

                        If CmbMoveTo.SelectedIndex = -1 Then
                            MsgBox("Select a 'Move To' location from the drop down list!", vbExclamation, "Error")
                            Exit Sub
                        Else
                            MoveLocation = strPath & "\" & CmbMoveTo.SelectedItem & "\" & fileDropped.Name
                        End If

                        Dim result As DialogResult = MessageBox.Show("Do you want to split this job?", "Job Split", MessageBoxButtons.YesNoCancel)

                        If result = DialogResult.Yes Then
                            NewFile = InputBox("Enter the quantity you are moving to: " & vbCrLf & vbCrLf & CStr(.Tag), "Update", fileDropped.Name)

                            If NewFile.Contains("__SPLIT") Then
                                MoveLocation = strPath & "\" & CStr(CmbMoveTo.SelectedValue) & "\" & NewFile
                            Else
                                MoveLocation = strPath & "\" & CStr(CmbMoveTo.SelectedValue) & "\" & NewFile & "__SPLIT"
                            End If

                            File.Copy(FileToMove, MoveLocation)
                            DirectCast(sender, ListBox).Items.Add(New DirectoryInfo(strPath & "\" & CStr(.Tag)).GetFiles.Where(Function(fi) fi.FullName = MoveLocation).FirstOrDefault)
                            Try
                                Using sw As New StreamWriter(File.Open(MoveLocation, FileMode.OpenOrCreate))
                                    sw.WriteLine("Moved To," & CStr(CmbMoveTo.SelectedValue) & "," & DateTime.Now & "," & NewFile & ",Job Split")
                                End Using
                            Catch ex As Exception
                                MsgBox("File Update Error!" & vbCrLf & ex.Message)
                            End Try

                        ElseIf result = DialogResult.Cancel OrElse result = DialogResult.No Then

                            File.Move(FileToMove, MoveLocation)
                            .Items.Add(New DirectoryInfo(strPath & "\" & CmbMoveTo.SelectedValue).GetFiles.Where(Function(fi) fi.FullName = MoveLocation).FirstOrDefault)

                            Try
                                Using sw As New StreamWriter(File.Open(MoveLocation, FileMode.Append))
                                    sw.WriteLine("Moved To," & CmbMoveTo.SelectedValue & "," & DateTime.Now & "," & fileDropped.Name)
                                End Using
                            Catch ex As Exception
                                MsgBox("File Update Error!" & vbCrLf & ex.Message)
                            End Try
                        End If

                    Else
                        File.Move(FileToMove, MoveLocation)
                        .Items.Add(New DirectoryInfo(strPath & "\" & CStr(.Tag)).GetFiles.Where(Function(fi) fi.FullName = MoveLocation).FirstOrDefault)

                        Try
                            Using sw As New StreamWriter(File.Open(MoveLocation, FileMode.Append))
                                sw.WriteLine("Moved To," & CStr(.Tag) & "," & DateTime.Now & "," & fileDropped.Name)
                            End Using
                        Catch ex As Exception
                            MsgBox("File Update Error!" & vbCrLf & ex.Message)
                        End Try
                    End If
                End With
            End If
        Catch ex As Exception
            MsgBox("Duplicate Job Detected... " & ex.Message, vbExclamation, "File Error")
        End Try


    End Sub

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Debug your code. You'll be able to see where it's using Nothing where a value is expected. Then, if you still need help, you'll be able to tell us.

Why do you feel it needs more efficiency added? Is the performance too slow?

InputBox is a bad idea. That function has a rather fatal flaw that you can't always live with for long. The problem is that you can't tell whether the user pressed Cancel or OK (with no entry). Because of that, the user ends up kind of trapped. Even if they press Cancel...things continue. In this case, either one will result in something kind of bad.

Please don't edit existing posts after others have replied unless it is to correct a mistake. If you do edit a previous post, it's a good idea to add a new post that points that out. Otherwise, there's every chance that your edit won't be seen.