How To Use JScript or JavaScript to Traverse Through a Collection (229693)

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The examples in this article use the file system object to traverse a folder (in this case, C:\Text) and list all the files located in the folder. The first example uses a FOR EACH...NEXT loop in VBScript to traverse:

Create a new folder in the root folder of drive C and name it "Text".
Place five text files in the directory you just created.
Create a new ASP page and add the following VBScript code:

<% @LANGUAGE="VBScript" %>
<%
	'Reference the FileSystemObject
	set FSO = Server.CreateObject("Scripting.FileSystemObject")
	
	'Reference the Text directory
	set Folder = FSO.GetFolder("C:\Text")

	'Reference the File collection of the Text directory
  	set FileCollection = Folder.Files

	Response.Write("VBScript Method<BR>")

	'Display the number of files within the Text directory
	Response.Write("Number of files found: " & FileCollection.Count & "<BR>")

	'Traverse through the FileCollection using the FOR EACH...NEXT loop
	For Each FileName in FileCollection

	   strFileName = FileName.Name
	   Response.Write(strFileName & "<BR>")

	Next

	'De-reference all the objects
	set FileCollection = Nothing
	set Folder = Nothing
	set FSO = Nothing

%>

The following example demonstrates the equivalent but uses JScript or JavaScript and the enumerator object as shown below. Follow the steps outlined previously, except use the following code in step 3.

<% @LANGUAGE="JScript" %>
<%
	// Reference the FileSystemObject
	var FSO = Server.CreateObject("Scripting.FileSystemObject");
	
	// Reference the Text directory
	var Folder = FSO.GetFolder("c:\\Text");

	// Reference the File collection of the Text directory
  	var FileCollection = Folder.Files;

	Response.Write("JScript Method<BR>");

	// Display the number of files within the Text directory
	Response.Write("Number of files found: " + FileCollection.Count + "<BR>");

	// Traverse through the FileCollection using the FOR loop
	for(var objEnum = new Enumerator(FileCollection); !objEnum.atEnd(); objEnum.moveNext()) {
	   strFileName = objEnum.item();
	   Response.Write(strFileName + "<BR>");
	}

	// Destroy and de-reference enumerator object
	delete objEnum;
	objEnum = null;

	// De-reference FileCollection and Folder object
	FileCollection = null;
	Folder = null;

	// Destroy and de-reference FileSystemObject
	delete FSO;
	FSO = null;
%>

NOTE: The enumerator object is instantiated within the FOR loop, which is okay in JScript or JavaScript. The syntax for the FOR statement is as follows:

FOR(initialize ; test ; increment)
statement;

The output for each example in this article will appear differently. In VBScript, the output shows only the file name and its file extension as shown here:

VBScript Method
Number of files found: 5
test1.txt
test2.txt
test3.txt
test4.txt
test5.txt

In JScript or JavaScript, the output displays the physical folder, the file name, and its file extension:

JScript Method
Number of files found: 5
C:\Text\test1.txt
C:\Text\test2.txt
C:\Text\test3.txt
C:\Text\test4.txt
C:\Text\test5.txt

The third-party products that are discussed in this article are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, regarding the performance or reliability of these products.

How To Use JScript or JavaScript to Traverse Through a Collection (229693)

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