Learn to Program with Small Basic

Let’s experiment with the first possibility to see what happens.
Path Doesn’t Exist
Run the short program in Listing 19-4.
1 ' BadPath.sb
2 path = "C:\Temp\Folder1\Out.txt"
3 res = File.WriteContents(path, "Hello")
4 TextWindow.WriteLine(res + ": " + File.LastError)
Listing 19-4: Writing to a file when the path doesn’t exist
You should see this output:
FAILED: Could not find a part of the path 'C:\Temp\Folder1\Out.txt'.
The program attempts to write the string "Hello" to an output file
(lines 2–3). The directory Temp exists, but the subdirectory Folder1 doesn’t
exist, so WriteContents() fails.
Appending to a File
The AppendContents() method opens the specified file and adds data to the
end of the file without erasing its original contents. AppendContents() takes
two arguments: the pathname of the output file and the string you want
to append to the end of the file. If the operation is successful, the method
returns "SUCCESS"; otherwise, it returns "FAILED". If the file you pass to
AppendContents() doesn’t exist, it’s created for you, and the string is written
to it. If the file already exists, the string is appended to its end.
To see the AppendContents() method in use, let’s say you need to maintain
a log file that records actions, errors, and other events in your program.
To keep the program simple, let’s just record the times when your
program is executed. Every time your program runs, you add a record to
a log file that includes the date and time. The complete program is shown
in Listing 19-5.
1 ' AppendContentsDemo.sb
2 outFile = Program.Directory + "\Log.txt"
3
4 strLog = Clock.WeekDay + ", " + Clock.Date + ", " + Clock.Time
5 result = File.AppendContents(outFile, strLog)
6 If (result = "FAILED") Then
7 TextWindow.WriteLine("Failed to write to: " + outFile)
8 TextWindow.WriteLine(File.LastError)
9 EndIf
10
11 TextWindow.WriteLine("Thank you for using this program. And for using
deodorant.")
Listing 19-5: Demonstrating the AppendContents() method
Receiving File Input and Output 295