checking for text from a text file

[Muzamil]

Helo Guyz,
i am kinda newbie to vb plz could somone help me on this?
I have a file for exapmle Named "test.dat" and it contains some text like
"hello"
"world"
"ugly"
"fear" and so on now on my form i have a list box and a textbox and a command button too.

when i click on the command button the text tht is contained in the textbox is added to the listbox.

wht i want to check is when i add the text to the listbox i want to check if the text in the text box is in the file "test.dat" if not then it wont b added. i hope u understand.

[Phill64]

hi,

i have written a sample for you and added alot of commenting to explain what is going on, since this is actually more involved then you may think. It involves playing with byte arrays, file streams and encoding.

you need to read the file and store it in an array, which you then test for the text being added, i have done this and the testing for the text in one sub.. but in reality you should read the file once only and test multiple times (unless you need it to keep updating)

Dim stringList() As String 'will be the end resulted file
        Dim fileBlog As String 'file blog (entire content in a string)
 
        'open file, create a filestream object
        Dim fileStream As New IO.FileStream(Application.StartupPath & "\test.txt", IO.FileMode.Open)
 
        'prepare an array of bytes
        Dim fileBytes(fileStream.Length) As Byte 'array of file bytes
        fileStream.Read(fileBytes, 0, fileStream.Length) 'read bytes of files into byte array
 
        'close file
        fileStream.Close()
 
        'convert file bytes into ASCII text
        fileBlog = System.Text.Encoding.ASCII.GetString(fileBytes)
 
        'split fileblog into seperate strings of text
        'a new line is ASCII characters 10 and 13
        'so we will remove 10, and split at 13
        fileBlog = Replace(fileBlog, Chr(10), "") 'remove 10
        stringList = fileBlog.Split(Chr(13)) 'split at 13, populate string array
 
        'check that text from textbox1 is not in the string array
        If Array.IndexOf(stringList, TextBox1.Text) = -1 Then
            MsgBox("not in array")
        Else
            MsgBox("IN ARRAY!")
        End If

[gigemboy]

Heres something a little simpler...

Dim strEnter As String = "hello" 'set this value equal to the string you want to check
Dim strSearch As String
        For Each strSearch In ListBox1.Items
            If strSearch = strEnter Then 'if strings are equal
                MsgBox("already entered!")
                Exit Sub
            Else
                ListBox1.Items.Add(strEnter) 'adds it, because it is different
            End If
        Next

[Phill64]

actually gigemboy,

your example searhes a listbox, not a file.
also, you do not need to scroll through every item.
there are pre-existing functions for all arrays in .net

so your code would be much smaller and efficient as this

Dim strEnter As String = "hello" 'set this value equal to the string you want to check
        If ListBox1.Items.Contains(strEnter) Then 'if string is in listbox
            MsgBox("already entered!")
        Else
            ListBox1.Items.Add(strEnter) 'adds it, because it is different
        End If

[gigemboy]

thx Phil.. If you read my signature, I'm still a lil new at this myself Never used the "contains" method before, but I know about it now