Working with Files

Статья
07/17/2015

There are two major categories of file manipulation:

Creating, adding, or removing data, and reading files
Moving, copying, and deleting files

Creating Files

There are three ways to create an empty text file (sometimes referred to as a "text stream").

The first way is to use the CreateTextFile method. The following example demonstrates how to create a text file using the CreateTextFile method.

Dim fso, f1
Set fso = CreateObject("Scripting.FileSystemObject")
Set f1 = fso.CreateTextFile("c:\testfile.txt", True)

var fso, f1;
fso = new ActiveXObject("Scripting.FileSystemObject");
f1 = fso.CreateTextFile("c:\\testfile.txt", true);

The second way to create a text file is to use the OpenTextFile method of the FileSystemObject object with the ForWriting flag set.

Dim fso, ts
Const ForWriting = 2
Set fso = CreateObject("Scripting. FileSystemObject")
Set ts = fso.OpenTextFile("c:\test.txt", ForWriting, True)

var fso, ts;
var ForWriting= 2;
fso = new ActiveXObject("Scripting.FileSystemObject");
ts = fso.OpenTextFile("c:\\test.txt", ForWriting, true);

A third way to create a text file is to use the OpenAsTextStream method with the ForWriting flag set.

Dim fso, f1, ts
Const ForWriting = 2
Set fso = CreateObject("Scripting.FileSystemObject")
fso.CreateTextFile ("c:\test1.txt")
Set f1 = fso.GetFile("c:\test1.txt")
Set ts = f1.OpenAsTextStream(ForWriting, True)

var fso, f1, ts;
var ForWriting = 2;
fso = new ActiveXObject("Scripting.FileSystemObject");
fso.CreateTextFile ("c:\\test1.txt");
f1 = fso.GetFile("c:\\test1.txt");
ts = f1.OpenAsTextStream(ForWriting, true);

Adding Data to the File

Once the text file is created, add data to the file using the following three steps:

Open the text file.

Write the data.

Close the file.

To open an existing file, use either the OpenTextFile method of the FileSystemObject object or the OpenAsTextStream method of the File object.

To write data to the open text file, use the Write, WriteLine, or WriteBlankLines methods of the TextStream Object, according to the tasks outlined in the following table.

Task	Method
Write data to an open text file without a trailing newline character.	Write
Write data to an open text file with a trailing newline character.	WriteLine
Write one or more blank lines to an open text file.	WriteBlankLines

To close an open file, use the Close method of the TextStream object.

Note

The newline character contains a character or characters (depending on the operating system) to advance the cursor to the beginning of the next line (carriage return/line feed). Be aware that the end of some strings may already have such nonprinting characters.

The following example demonstrates how to open a file, use all three write methods to add data to the file, and then close the file:

Sub CreateFile()
   Dim fso, tf
   Set fso = CreateObject("Scripting.FileSystemObject")
   Set tf = fso.CreateTextFile("c:\testfile.txt", True)
   ' Write a line with a newline character.
   tf.WriteLine("Testing 1, 2, 3.") 
   ' Write three newline characters to the file.        
   tf.WriteBlankLines(3) 
   ' Write a line.
   tf.Write ("This is a test.") 
   tf.Close
End Sub

function CreateFile()
{
   var fso, tf;
   fso = new ActiveXObject("Scripting.FileSystemObject");
   tf = fso.CreateTextFile("c:\\testfile.txt", true);
   // Write a line with a newline character.
   tf.WriteLine("Testing 1, 2, 3.") ;
   // Write three newline characters to the file.
   tf.WriteBlankLines(3) ;
   // Write a line.
   tf.Write ("This is a test.");
   tf.Close();
}

Reading Files

To read data from a text file, use the Read, ReadLine, or ReadAll method of the TextStream Object. The following table describes which method to use for various tasks.

Task	Method
Read a specified number of characters from a file.	Read
Read an entire line (up to, but not including, the newline character).	ReadLine
Read the entire contents of a text file.	ReadAll

If you use the Read or ReadLine method and want to skip to a particular portion of data, use the Skip or SkipLine method. The resulting text of the read methods is stored in a string which can be displayed in a control, parsed by string functions (such as Left, Right, and Mid), concatenated, and so forth.

Use the AtEndOfStream property to check whether a file pointer has reached the end of TextStream Object file.

The following example demonstrates how to open a file, write to it, and then read from it:

Sub ReadFiles
   Dim fso, f1, ts, s
   Const ForReading = 1
   Set fso = CreateObject("Scripting.FileSystemObject")
   Set f1 = fso.CreateTextFile("c:\testfile.txt", True)
   ' Write a line.
   Response.Write "Writing file <br>"
   f1.WriteLine "Hello World"
   f1.WriteBlankLines(1)
   f1.Close
   ' Read the contents of the file.
   Response.Write "Reading file <br>"
   Set ts = fso.OpenTextFile("c:\testfile.txt", ForReading)
   s = ts.ReadLine
   Response.Write "File contents = '" & s & "'"
   ts.Close
End Sub

function ReadFiles()
{
   var fso, f1, ts, s;
   var ForReading = 1;
   fso = new ActiveXObject("Scripting.FileSystemObject");
   f1 = fso.CreateTextFile("c:\\testfile.txt", true);
   // Write a line.
   Response.Write("Writing file <br>");
   f1.WriteLine("Hello World");
   f1.WriteBlankLines(1);
   f1.Close();
   // Read the contents of the file.
   Response.Write("Reading file <br>");
   ts = fso.OpenTextFile("c:\\testfile.txt", ForReading);
   s = ts.ReadLine();
   Response.Write("File contents = '" + s + "'");
   ts.Close();
}

Moving, Copying, and Deleting Files

The FSO object model has two methods each for moving, copying, and deleting files, as described in the following table.

Task	Method
Move a file	File.Move or FileSystemObject.MoveFile
Copy a file	File.Copy or FileSystemObject.CopyFile
Delete a file	File.Delete or FileSystemObject.DeleteFile

The following example creates a text file in the root directory of drive C, writes some information to it, moves it to a directory called \tmp, makes a copy of it in a directory called \temp, then deletes the copies from both directories.

To run the following example, create directories named \tmp and \temp in the root directory of drive C:

Sub ManipFiles
   Dim fso, f1, f2, s
   Set fso = CreateObject("Scripting.FileSystemObject")
   Set f1 = fso.CreateTextFile("c:\testfile.txt", True)
   Response.Write "Writing file <br>"
   ' Write a line.
   f1.Write ("This is a test.")
   ' Close the file to writing.
   f1.Close
   Response.Write "Moving file to c:\tmp <br>"
   ' Get a handle to the file in root of C:\.
   Set f2 = fso.GetFile("c:\testfile.txt")
   ' Move the file to \tmp directory.
   f2.Move ("c:\tmp\testfile.txt")
   Response.Write "Copying file to c:\temp <br>"
   ' Copy the file to \temp.
   f2.Copy ("c:\temp\testfile.txt")
   Response.Write "Deleting files <br>"
   ' Get handles to files' current location.
   Set f2 = fso.GetFile("c:\tmp\testfile.txt")
   Set f3 = fso.GetFile("c:\temp\testfile.txt")
   ' Delete the files.
   f2.Delete
   f3.Delete
   Response.Write "All done!"
End Sub

function ManipFiles()
{
   var fso, f1, f2, s;
   fso = new ActiveXObject("Scripting.FileSystemObject");
   f1 = fso.CreateTextFile("c:\\testfile.txt", true);
   Response.Write("Writing file <br>");
   // Write a line.
   f1.Write("This is a test.");
   // Close the file to writing.
   f1.Close();
   Response.Write("Moving file to c:\\tmp <br>");
   // Get a handle to the file in root of C:\.
   f2 = fso.GetFile("c:\\testfile.txt");
   // Move the file to \tmp directory.
   f2.Move ("c:\\tmp\\testfile.txt");
   Response.Write("Copying file to c:\\temp <br>");
   // Copy the file to \temp.
   f2.Copy ("c:\\temp\\testfile.txt");
   Response.Write("Deleting files <br>");
   // Get handles to files' current location.
   f2 = fso.GetFile("c:\\tmp\\testfile.txt");
   f3 = fso.GetFile("c:\\temp\\testfile.txt");
   // Delete the files.
   f2.Delete();
   f3.Delete();
   Response.Write("All done!");
}

Change History

Date	History	Reason
April 2009	Added links to TextStream Object.	Customer feedback.

April 2009

Added links to TextStream Object.

Customer feedback.

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