Introduction:
This tutorial is going to be on how to create a record management solution in Visual Basic.

This Tutorial:
Since this is a multi-part tutorial series, this tutorial is going to be on creating the first part of the filter records GUI.

What Will Filtering Do?
The filtering within the program will allow the user to filter through the entire file of results and perform additional changes to any single record or a group of records based off the filtering criteria.

The filtering GUI will allow the user to search by a single piece of information, a group of pieces of information, or index numbers.

To create the GUI, go to Project > Add Windows Form... > select Windows Form, name it filterGUI and click OK.

The Design:
Before we can create any code for the filtering GUI, we need to create the design for the GUI. The GUI will contain;
Textbox - named filterText - to allow the user to enter search criteria.
Button - named filterButton, text set to "Fitler" - to allow the user to begin the filtering/searching process.
Listbox - named filterList - to list each of the records returned from the filtering/searching process.
Button - named delButton, text set to "Delete" - deletes the selected records.
Button - named modifyButton, text set to "Modify" - lets the user modify that specific record.
Button - named copyButton, text set to "Copy" - lets the user copy the selected record(s) to their clipboard.

The Filtering Function:
We won't be making any of the actual buttons within the design work in this tutorial so instead we are going to create a function which will be used once one or more of the buttons have been pressed, the filtering function.

This function will take a string of information to filter the results through, and an option list of records - if there are no parsed records, we will start from fresh from the management file.

1. Imports System.IO
   
2. 
   
3. Public
   
   Class filterGUI
   
4. Private
   
   Function
   
   filterRecords(ByVal
   
   filter As
   
   String
   
   , Optional
   
   ByVal
   
   records As
   
   List(Of String
   
   ) = Nothing
   
   )
   
5. Dim
   
   recs As
   
   List(Of String
   
   ) = New
   
   List(Of String
   
   )
   
6. If
   
   (Not
   
   records Is
   
   Nothing
   
   ) Then
   
7. For
   
   Each
   
   s As
   
   String
   
   In
   
   records
   
8. recs.Add(s)
   
9. Next
   
10. Else
    
11. 'Get from file
    
12. Using sr As
    
    New
    
    StreamReader(Form1.filePath)
    
13. While
    
    (sr.Peek <> -1)
    
14. recs.Add(sr.ReadLine())
    
15. End
    
    While
    
16. End
    
    Using
    
17. End
    
    If
    
18. If
    
    (recs.Count > 0) Then
    
19. Dim
    
    retRecords As
    
    List(Of String
    
    ) = New
    
    List(Of String
    
    )
    
20. For
    
    Each
    
    record As
    
    String
    
    In
    
    recs
    
21. If
    
    (record.Contains(filter)) Then
    
    retRecords.Add(record)
    
22. Next
    
23. Return retRecords
    
24. Else
    
    : MsgBox("No records found!"
    
    )
    
25. End
    
    If
    
26. Return ""
    
27. End
    
    Function
    
28. End
    
    Class
    

This function gets all the available records (either from the parameter records or from the management file if no records are parsed to the records parameter), then iterates through them adding each one that contains the filtering string (from the arguments/parameters of the function, 'filter') to a new list of strings. It then returns the list of strings which all contain the filtering string. If an error occurs or no filtered records are found, a blank string is returned 'Return ""'