Compare Text Files

I'm trying to compare two text files and have the difference displayed.
The code below displays both text files, just haven't figured out how to get what's not in either file.

FileOpen(1, File1.Value, OpenMode.Input, OpenAccess.Read, OpenShare.Shared)
FileOpen(2, File2.Value, OpenMode.Input, OpenAccess.Read, OpenShare.Shared)
Do While Not EOF(1)
Dim TextLine As String = LineInput(1)
Response.Write(TextLine)
Response.Write("<br>")
Loop
FileClose(1)

Do While Not EOF(2)
Dim TextLine2 As String = LineInput(2)
Response.Write(Textline2)
Response.Write("<br>")
Loop
FileClose(2)

Or if you have a better way of comparing two text files I'm open. I'm using vb.net and running a web form.
Thanks

Read each file, line by line and store it in an array. Then loop through the arrays and simply check whether each element of the array (by ordinal) matches the other one. If they match, do nothing, if they don't match, mark them.

Finally, when displaying the two test files, make sure you 'highlight' the differing lines in your display.

For a straight compare the easiest way would be to hash the files and then compare the hashes.

Thanks for responding. I've managed to get the code where it's reading and writing data to the console. Would ultimately want it in a listbox or datagrid though. But anyway, when the lines are displayed it's multiple lines on one line.

I'm getting below on one line. A separate line should begin with CO574.

CO574.GL,11100,21 CO574.GL,12110.01,3970 CO574.GL,12110.02,1104 CO574.GL,12110.02,4

Here's the code that produce the results above.

For Each strFile1Line As String In strFile1Lines
Dim bLineInFile2 As Boolean = False

' Compare the current line in File1 against all lines in File2
For Each strFile2Line As String In strFile2Lines
If strFile1Line = strFile2Line Then bLineInFile2 = True

Next

' If the line is in not in File2 add it to the variable strFile1NotFile2
If Not bLineInFile2 Then strFile1NotFile2 = strFile1NotFile2 & vbCrLf & strFile1Line & vbCrLf

Next
Response.Write(strFile1NotFile2 & vbCrLf)
Response.Write("<br>")

I figured it out and it's working the way I want it to on small files. When I try to read a large files it returns "page not found". These files are about 5k, but my ultimate goal is to read files much larger, maybe 30-50mb. Any ideas how to get around current problem?

Just a followup to see if there are any ideas. Thanks.

Why not use Active File Compare

It's been 2 years...

BeyondCompare 2. Wonderful software. Even connects over networks and FTP.