How to close instance of an XML DOCUMENT - vb.net

Question

While attempting to issue the SAVE of the XmlDocument class on an XML document, specifically on this line of code:
myXmlDocument.Save(strFileZillaFilePathAndName).
I get... During entry update - save of FileZilla file failed. The process cannot access the file 'C:\Program Files (x86)\FileZilla Server\FileZilla Server.xml' because it is being used by another process.
It occurs in the FindAndUpdateXMLEntries(...) method called from within my UpdateFtpAccountsProcess(...) function.
I thought that this use of the SAVE did not require a close.
It happens on a 2nd execution of the function so it seems that the file is not being closed. It should be closed by the 1st execution and it is not be being used by another process
Public Function UpdateFtpAccountsProcess(ByVal strIpAddress As String, ByVal strPassword As String, ByVal iBackupSpaceId As Integer, ByVal iFtpAccountId As Integer, ByVal strFtpAccountPassword As String, ByVal strAccountType As String) As Boolean Implements IBackupServerService.UpdateFtpAccountsProcess
Dim strErrorMessage As String = ""
' Start the backup service logging.
StartTheLog(iBackupSpaceId)
' Write an log entry.
strInputLogMessage = "In UpdateFtpAccountsProcess method."
LogAnEntry(strInputLogMessage)
' Validate the password arguement in order to use this WCF service method.
' Read the app.config files "appSettings" section to get the backup server password. If it matches, continue.
strEncryptedBackupServerPassword = GetAppSetting(strKeyPassword)
If strEncryptedBackupServerPassword = strPassword Then
' Update the FTP account's encrypted password by "backup space id" and "account type". The accounts are stored in the FileZilla Server.xml file.
' Read the app.config file to get the “FileZilla path and name”.
strFileZillaFilePathAndName = GetAppSetting(strKeyFileZilla)
' Read the app.config file to get the “FileZilla Application path and name”.
strFileZillaFileApplicationPathAndName = GetAppSetting(strKeyFileZillaApplication)
If ((strFileZillaFilePathAndName = "Not Found" Or strFileZillaFilePathAndName = "Error") Or (strFileZillaFileApplicationPathAndName = "Not Found" Or strFileZillaFileApplicationPathAndName = "Error")) Then
strErrorMessage = "During update of FTP accounts - cannot find the FileZilla entries in the app config. Space Id: " & iBackupSpaceId.ToString()
Else
Try
' Read the XML file and update the "password" of 1 of the 2 User entries [ftp accounts] - for the "backup space id".
FindAndUpdateXMLEntries(strFileZillaFilePathAndName, iBackupSpaceId, strFtpAccountPassword, strAccountType)
Try
' Execute command to run the FileZilla application to have FileZilla re-read the configuration.
ReloadFileZillaConfig(strFileZillaFileApplicationPathAndName)
Catch ex As Exception
strErrorMessage = "From: ReloadFileZillaConfig() ---> " & ex.Message
End Try
Catch ex As Exception
' Attach the message coming from the FindAndUpdateXMLEntries() method.
strErrorMessage = "During update of FTP account - Space Id: " & iBackupSpaceId.ToString() & " from: FindAndUpdateXMLEntries() ---> " & ex.Message
End Try
End If
Else
strErrorMessage = "During update of FTP accounts - invalid backup server password. It must match the app.config entry. Space Id: " & iBackupSpaceId.ToString()
End If
If strErrorMessage <> "" Then
Throw New System.Exception(strErrorMessage)
End If
' End the backup service logging.
EndTheLog()
Return bSuccess = True
End Function
Public Sub FindAndUpdateXMLEntries(ByVal strFileZillaFilePathAndName As String, ByVal iBackupSpaceId As Integer, ByVal strFtpAccountPassword As String, ByVal strAccountType As String)
Dim strErrorMessage As String = ""
Dim xmlNode1 As XmlNode
Dim xmlNode2 As XmlNode
Dim xmlNode3 As XmlNode
Dim strUserNodeAtrributeNameValue As String
Dim strUnderUserNodeThisNodesAtrributeNameValue As String
Dim bSuccess As Boolean = False
' The XmlDocument class represents the XML document and has a Load method to load the document from a file, stream, or an XmlReader.
' So load in the XML file.
Dim myXmlDocument As XmlDocument = New XmlDocument()
' Write an log entry.
strInputLogMessage = "In FindAndUpdateXMLEntries method."
LogAnEntry(strInputLogMessage)
Try
' Load in the XML file.
myXmlDocument.Load(strFileZillaFilePathAndName)
' Use the XmlNode object that the DocumentElement property of the XmlDocument returns to manipulate an XML node.
xmlNode1 = myXmlDocument.DocumentElement
' Field to match to under the "Users" node. Building the "#-Private" or "#-Private" User root node.
strUserNodeAtrributeNameValue = iBackupSpaceId.ToString() & "-" & strAccountType.Trim()
' The next field to match to under the "User" node that I find.
strUnderUserNodeThisNodesAtrributeNameValue = "Pass"
' Iterate thru to find the node to update.
For Each xmlNode1 In xmlNode1.ChildNodes
If xmlNode1.Name = "Users" Then
' Find the child nodes in "Users" only.
For Each xmlNode2 In xmlNode1.ChildNodes
' Find the "User" node that I want.
If xmlNode2.Attributes("Name").Value = strUserNodeAtrributeNameValue Then
For Each xmlNode3 In xmlNode2.ChildNodes
' Find the node that I want that is under the "User" node. Looking for: <Option Name="Pass">some value</Option>
If xmlNode3.Attributes("Name").Value = strUnderUserNodeThisNodesAtrributeNameValue Then
' Update the XML to the new password value.
xmlNode3.InnerText = strFtpAccountPassword
bSuccess = True
Exit For
End If
If bSuccess = True Then
Exit For
End If
Next
End If
Next
End If
If bSuccess = True Then
Exit For
End If
Next
If bSuccess = True Then
Try
' Use the Save method of the XmlDocument class to save the altered XML back to the input XML file.
myXmlDocument.Save(strFileZillaFilePathAndName)
Catch ex As Exception
strErrorMessage = "During entry update - save of FileZilla file failed. " & ex.Message
End Try
Else
strErrorMessage = "During entry update - No User node to update"
End If
Catch ex As Exception
strErrorMessage = "During entry update - load of FileZilla file failed. " & ex.Message
End Try
If strErrorMessage <> "" Then
Throw New System.Exception(strErrorMessage)
End If
End Sub