Home > Articles > Programming > Visual Basic

  • Print
  • + Share This
Like this article? We recommend

Saving and Retrieving the User's State

Now that we know what we need to save, let's code the GetState and SaveState methods that actually read the write the data values. This PublishersWebUI sample application will save the state data for each user into a simple CSV text file in which the filename is based on the UserID property value. I like using CSV files during initial development of Web applications because it's simple to change what gets written to them, and because it's a simple enough matter to open them with Notepad to make sure that everything is being saved correctly. After your application design stabilizes (maybe I should say if it ever stabilizes), you might consider changing it to instead write the data to a binary file or to a table in a relational database.

The logic to save the state information is very simple:

  1. Open a CSV file for output destroying the previous contents if it already exists.

  2. Write the search filter value to a record.

  3. Write the number of selected authors in the collection to a record. This simplifies retrieving them later.

  4. For each author in the collection, write the Publisher ID, Publisher Name, and Publisher Phone.

The source code for the SaveState method looks like this:

' Saves all state information to a simple CSV file.
Public Sub SaveState()
  Dim lFileNbr  As Integer
  Dim lPubState As clsPubState
  lFileNbr = FreeFile
  Open StateFileName For Output As lFileNbr
  ' Save the state data.
  Write #lFileNbr, Filter
  Write #lFileNbr, Publishers.Count
  For Each lPubState In Publishers
    Write #lFileNbr, lPubState.PubID, lPubState.Name, lPubState.Phone
  Next lPubState
  Close lFileNbr
End Sub

Both the SaveState and GetState methods use the StateFileName Private Property procedure:

Private Property Get StateFileName() As String
  StateFileName = App.Path & "\" & mUserID & ".usf"
End Property

This property simply returns the fully qualified filename for the state file. In my example, I'm creating the state filename by simply suffixing the UserID property value with .usf (User State File) and saving it to the same folder as where the component is installed. In reality, the path for the state files should be configurable from an INI file option or a registry setting.

For clsUserState to restore the state information, the GetState method generally works like the SaveState method in reverse. However, there are a couple of exceptions to handle. The first one is that we should expect that sometimes the state file won't exist. This could happen because of the following:

  • This is the first request from the user and we haven't written any state information yet.

  • The state file has expired and been deleted by our external process.

  • The uid query string value has been altered by the user somehow. In this case, the uid query string value will be used to create the state filename as long as it contains valid characters that can be used when naming a file. If it contains invalid characters, the operating system will raise a run-time error, so it might be a good idea to generate a new UserID value if the file cannot be opened.

In all cases, if the file doesn't exist, there is no state information to restore so the Filter and Publishers properties should contain default values.

The second exception to check is to make sure that even if a state file is found, it doesn't have expired data in it. Comparing the modified date/time of the state file with the current system time easily does this. The expiration period can be whatever you want—minutes, hours, and even days or months. If the difference is greater than whatever you want the expiration period to be, simply ignore the contents of the file, and again the Filter and Publishers properties should contain default values. In my example, I assume the state data has expired if the file hasn't been used in the last 60 minutes.

My completed GetState method looks like this:

' Attempt to restore the state information from the CSV file.
' If the state file is not found, or the data in the file hasn't
' been used in the last 60 minutes, then we assume a new session.
Public Sub GetState()
  Dim lFileNbr  As Integer
  Dim lNbrPubs  As Long
  Dim lIndex   As Long
  Dim lID    As Long
  Dim lName   As String
  Dim lPhone   As String
  Dim lPubState As clsPubState
  Filter = ""
  Set Publishers = New Collection
  lFileNbr = FreeFile
  On Error Resume Next
  Open StateFileName For Input As lFileNbr
  'If file not found, then that means no state information exists.
  If Err.Number = 53 Then ' 53 = File Not Found.
    Exit Sub
  ElseIf Err.Number <> 0 Then
    Call Err.Raise(Err.Number, Err.Source, Err.Description)
  End If
  On Error GoTo 0 ' Reset error handling so run-time errors get raised.
  ' If state information is > 60 minutes old, then ignore it.
  If DateDiff("n", FileDateTime(StateFileName), Now) > 60 Then
    Close lFileNbr
    Exit Sub
  End If
  ' Get the state data.
  Input #lFileNbr, Filter
  Input #lFileNbr, lNbrPubs
  For lIndex = 1 To lNbrPubs Step 1
    Set lPubState = New clsPubState
    ' Note the syntax of the Input statement won't allow us to input
    ' directly into an object's properties so instead we have to input
    ' into local variables and then assign to the object.
    Input #lFileNbr, lID, lName, lPhone
    lPubState.PubID = lID
    lPubState.Name = lName
    lPubState.Phone = lPhone
    Call Publishers.Add(lPubState)
  Next lIndex
  Close lFileNbr
End Sub
  • + Share This
  • 🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020