Free Guides
Language Tutorials
Visual Basic
14.1 Introduction
Up until lesson 13 we are only creating programs that could accept data at runtime, when the program is terminated, the
data also disappear. Is it possible to save data accepted by a VB program into a storage device, such as a hard disk or diskette,
or even CDRW? The answer is possible. In this chapter, we will learn how to create files by writing them into a storage device and
then retrieve the data by reading the contents of the files using a customized VB program.
14.2 Creating files
To create a file , we use the following command
Open "fileName" For Output As #fileNumber
Each file created must have a file name and a file number for identification. As for the file name, you must also specify the path where the file will reside.
Examples:
Open "c:\My Documents\sample.txt" For Output As #1
will create a text file by the name of sample.txt in My Document folder. The accompany file number is 1. If you wish to create and save the file in A drive,
simply change the path, as follows"
Open "A:\sample.txt" For Output As #1
If you wish to create a HTML file , simply change the extension to .html
Open "c:\My Documents\sample.html" For Output As # 2
14.2.1 Sample Program : Creating a text file
Private Sub create_Click()
Dim intMsg As
String
Dim StudentName
As String
Open "c:\My Documents\sample.txt"
For Output As #1
intMsg = MsgBox("File sample.txt opened")
StudentName = InputBox("Enter the student Name")
Print #1, StudentName
intMsg = MsgBox("Writing a" & StudentName & " to sample.txt ")
Close #1
intMsg =
MsgBox("File sample.txt closed")
End Sub
* The above program will create a file sample.txt in the My Documents' folder and ready to receive input
from users. Any data input by users will be saved in this text file.
14.3 Reading files
To read a file created in section 14.2, you can use the input # statement. However, we
can only read the file according to the format when it was written. You have to open the file
according to its file number and the variable that hold the data. We also need to declare the variable using the DIM command.
14.3.1 Sample Program: Reading file
Private Sub Reading_Click()
Dim variable1 As
String
Open "c:\My Documents\sample.txt"
For Input As #1
Input #1, variable1
Text1.Text = variable1
Close #1
End Sub