Read, Write Text Files, String Functions

Welcome to Visual Basic Beginner 201. In this course you will learn how to read and write sequential text files, break up delimited strings, and use string functions like InStr, Left, and Right. We'll also discuss Tab Index and Tab Stop properties, learn how to send parameters to subroutines, and see how to access course materials and participate in the class forum. Tips for following along with sample projects will be included, and familiarity with Visual Basic 107 is recommended.

Lessons

•  00. Introduction (2:02)
•  01. Writing Files (9:52)
•  02. Reading Text Files (19:57)
•  03. Writing Multiple Records (12:05)
•  04. Reading Multiple Records (9:30)
•  05. Break Up Strings (25:18)
•  06. Review & What's Next (4:46)
• Total Runtime: 1 hour 23 minutes

Resources

• Full Course Outline
•  Video ZIP File (32 MB)
•  PDF Handbook
• Certificate of Completion
• Post-Class Survey

Lesson Summary

Welcome! Text Files: Read, Write, Strings - In this lesson, we will introduce Visual Basic 201 and discuss how to read and write sequential text files, break up delimited strings, and use string functions like InStr, Left, and Right. We will also look at the Tab Index and Tab Stop properties, and show how to send parameters to your own subroutines. The class is based on Microsoft Visual Basic, and familiarity with Visual Basic 107 is recommended. We will cover how to access course materials and participate in the class discussion forum, and you will get tips for following along with the sample projects.

Lesson 1: Save User Input with FreeFile - In Lesson 1, we will walk through the basics of writing files in your program. I will show you how to open a text file for output, print data to it, and close the file when you are done. We will build a simple form to save customer information to a file, discuss how to avoid hard-coding file names, and introduce the FreeFile command to manage multiple open files efficiently. We will also talk about different file opening modes and touch on how storing data in text files can make your programs more user friendly.

Lesson 2: Read/Write Files & Save Settings - In Lesson 2, we will learn how to read information from text files in Visual Basic. We will cover opening files for input, using the Shell command to launch external programs like Notepad, and discuss how to load and save program information such as form size and user data. I will show you how to properly use the Line Input function to read text files, deal with common mistakes, and create your own subroutines to make your code reusable. By the end, you will know how to persist both user data and form settings between program sessions.

Lesson 3: Save List Box Records to File - In this lesson, we will walk through writing multiple records by adding customer information to a single list box and then saving all entries to a file at once. I will show you how to combine data fields into one list box, how to add records with a button, and how to loop through the list to save everything in a single step. We will also discuss improving usability by adjusting tab order, using the tab index and tab stop properties, and adding simple data validation to enhance the process of writing multiple records.

Lesson 4: List Box Multiple Records & Input Validation - In this lesson, we will learn how to read multiple records into a list box from a comma-delimited file. We will discuss adding validation to prevent users from entering commas in their input fields using the InStr function and the Validate event. I will show you how to use the EOF (end of file) marker to loop through records and load them into the list box. We will also talk about how to split and display these records, and I will provide an overview of how InStr can be used to validate input, such as checking for valid email addresses.

Lesson 5: Split Delimited Strings With InStr - In this lesson, we will learn how to break up strings containing multiple fields separated by commas, such as last name, first name, and phone number. I will show you how to use the InStr function to split these strings into separate fields, and we will walk through using the With keyword to simplify code when working with controls. We will also discuss sending a parameter to a subroutine, right-clicking to use the Definition feature in VBA, and using a second hidden list box to format data for display while storing the original string data in another list box.

Lesson 6: Text Files, Strings & Params - In this course we learned how to work with text files by reading and writing sequential text files, opening files for write access and reading for input, and breaking up comma-delimited strings. We covered string functions like InStr, Left, and Right, changing tab order, and sending parameters to subroutines. We also discussed what is next, including building a hot dog stand application, appending to text files, creating arrays and user-defined types, using Sub Main and modules, public subroutines, constants, additional functions, string manipulation, formatting techniques, date calculations, and resources for questions and feedback.

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