system.io.ioexception进程无法访问，因为它正被另一个进程使用

Question

我在某些系统中遇到此问题，某些系统正常工作，此处我的代码是

Dim fileName As String = "FaultTypesByMonth.csv"  
        Using writer As IO.StreamWriter = New IO.StreamWriter(fileName, True, System.Text.Encoding.Default)     '------------  rao new ----

            Dim Str As String
            Dim i As Integer
            Dim j As Integer           
            Dim headertext1(rsTerms.Columns.Count) As String
            Dim k As Integer = 0
            Dim arrcols As String = Nothing
            For Each column As DataColumn In TempTab.Columns

                arrcols += column.ColumnName.ToString() + ","c
                k += 1
            Next

            writer.WriteLine(arrcols)          

            For i = 0 To (TempTab.Rows.Count - 1)
                For j = 0 To (TempTab.Columns.Count - 1)

                    If j = (TempTab.Columns.Count - 1) Then
                        Str = (TempTab.Rows(i)(j).ToString)
                    Else
                        Str = (TempTab.Rows(i)(j).ToString & ",")
                    End If                    
                    writer.Write(Str)       
                Next               
                writer.WriteLine()
            Next          
            writer.Close()
            writer.Dispose()
        End Using                  

        Dim FileToDelete As String = Nothing
        Dim sd As New SaveFileDialog
        sd.Filter = "CSV Files (*.csv)|*.csv"
        sd.FileName = "FaultTypesByMonth"
        If sd.ShowDialog = Windows.Forms.DialogResult.OK Then            
            FileCopy(fileName, sd.FileName)               
            MsgBox(" File Saved in selected path")
            FileToDelete = fileName
            If System.IO.File.Exists(FileToDelete) = True Then
                System.IO.File.Delete(FileToDelete)
            End If           
        End If
        FileToDelete = fileName
        If System.IO.File.Exists(FileToDelete) = True Then
            System.IO.File.Delete(FileToDelete)
        End If

当我试图将此文件保存在所需的路径中时，我收到此错误。 如果保存在共享文件夹中我没有​​收到此错误

system.io.ioexception the process cannot access because it is being used by another process...

我做错了什么，帮帮我