I used the following code to create an Excel file from a dataset. However, the only way I can forward that file to the user is with a Response.Redirect(). If I try a Response.TransmitFile(), it will say that the file is in used by another process. If I try to directly open that file from the disk, it tells me the same thing.

Anyone can take a look at that code and see what kind of operation I should do in order to release that lock on the file?

        ' Export a dataset into an Excel spreadsheet
        ' expO1 DataSet
        ' expC1 Full path of the file to save
        Public Function ExportToExcel(ByVal toDataSet As DataSet, ByVal tcFile As String) As Boolean
            Dim lcFile As String = oApp.GenerateFileName()
            Dim lcXml As String = ""
            Dim lcXsl As String = ""
            Dim loFileStream As FileStream
            Dim loXml As Framework.XML
            Dim loXslCompiledTransform As Xsl.XslCompiledTransform = New Xsl.XslCompiledTransform

            ' Get the proper definition as per the current scope
            If oProcess Is Nothing Then
                loXml = New Framework.XML(oApp)
            Else
                loXml = New Framework.XML(oProcess)
            End If

            ' Load the Xml
            If Not loXml.LoadXml(oApp.DataSetToXml(toDataSet)) Then
                Return False
            End If

            ' Normalize the Xml
            If Not loXml.Normalize() Then
                Return False
            End If

            ' Get the Xml
            lcXml = loXml.cXml

            ' Add the French header because by default there isn't so we cover it all
            lcXml = loXml.AddHeaderForFrenchCharacter() + lcXml

            ' Save in a Xml file

            ' Get the proper definition as per the current scope
            If oProcess Is Nothing Then
                If Not oApp.CreateFile(lcXml, oApp.cHttpFat + "Temp\" + lcFile + ".xml") Then
                    Return False
                End If
            Else
                If Not oProcess.CreateFile(lcXml, oApp.cHttpFat + "Temp\" + lcFile + ".xml") Then
                    Return False
                End If
            End If

            ' Generate a Xsl string based on the dataset
            lcXsl = GetXsl()

            ' Save the Xsl file

            ' Get the proper definition as per the current scope
            If oProcess Is Nothing Then
                If Not oApp.CreateFile(lcXsl, oApp.cHttpFat + "Temp\" + lcFile + ".xsl") Then
                    Return False
                End If
            Else
                If Not oProcess.CreateFile(lcXsl, oApp.cHttpFat + "Temp\" + lcFile + ".xsl") Then
                    Return False
                End If
            End If

            ' Load the Xsl in memory
            loXslCompiledTransform.Load(oApp.cHttpFat + "Temp\" + lcFile + ".xsl")

            ' Load the target file in memory
            loFileStream = New FileStream(tcFile, FileMode.Create)

            ' Do the transformation
            Try
                loXslCompiledTransform.Transform(New XPath.XPathDocument(oApp.cHttpFat + "Temp\" + lcFile + ".xml"), Nothing, loFileStream)
            Catch loError As Exception

                ' Get the proper definition as per the current scope
                If oProcess Is Nothing Then
                    oApp.ErrorSetup(loError)
                Else
                    oProcess.ErrorSetup(loError)
                End If

                Return False
            End Try

            ' We can now remove the temporary files

            ' Get the proper definition as per the current scope
            If oProcess Is Nothing Then
                oApp.DeleteFile(oApp.cHttpFat + "Temp\" + lcFile + ".xml")
                oApp.DeleteFile(oApp.cHttpFat + "Temp\" + lcFile + ".xsl")
            Else
                oProcess.DeleteFile(oApp.cHttpFat + "Temp\" + lcFile + ".xml")
                oProcess.DeleteFile(oApp.cHttpFat + "Temp\" + lcFile + ".xsl")
            End If

            Return True
        End Function