Programming Forums - Object reference error

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- - Object reference error (http://www.programmingforums.org/showthread.php?t=14106)

Jabo	Oct 4th, 2007 4:04 AM

Object reference error

I'm trying to make a parser for a text file, but I'm getting an object reference error. Can somebody tell me why?

Dim filereader As String

        Dim parser() As String

        Dim ArrSize, i, j, x As Integer

        Dim word(), newword() As Char



        filereader = My.Computer.FileSystem.ReadAllText("m:\VC++Express\Open Media Distribution List[1].txt")

        parser = Split(filereader)

        ArrSize = parser.Length

        For i = 0 To ArrSize - 1

            word = parser(i).ToCharArray

            x = word.Length

            For j = 0 To x - 1

                If Char.IsLetterOrDigit(word(j)) Then

                    newword(newword.Length) = word(j)

                End If

            Next

            parser(i) = newword.ToString

            lboTSMTape.Items.Add(parser(i))

        Next

The red line has error attached to it saying object reference not set to an instance of an object

melbolt

Oct 4th, 2007 10:02 AM

let me see if I can explain this right.

here's the problem, you attempt to put something in the array newword but you never allocated any space for that array.

what i mean by this is, you never gave it bounds ex: newword(5) would allocate 5 indexes.

what you can do is this...

           word = parser(i).ToCharArray
           Dim newword(word.Length) As Char

the reason you didn't have to set up the word array like this is because you are not trying to utilize its indexes until you set it equal to an existing array(which does have allocated memory)
ex:

word = parser(i).ToCharArray

Jabo	Oct 4th, 2007 10:07 AM

Ahh, that makes a lot of sense, thanks melbolt. But now i'm gonna have to rethink my algorithm because the array will be different each time. Can you dynamically allocate a vector? I need to re-learn how to do a vector.

Jabo	Oct 5th, 2007 3:37 AM

Here's what I wound up doing; it's not elegant, but it does the job.

Dim filereader As String

        Dim parser() As String

        Dim ArrSize, i, j, x, y As Integer

        Dim word(30), newword(30) As Char



        filereader = My.Computer.FileSystem.ReadAllText(cboFileList.Text)

        parser = Split(filereader)

        ArrSize = parser.Length



        For i = 0 To ArrSize - 1

            word = parser(i).ToCharArray

            x = word.Length

            y = 0

            For j = 0 To 29

                newword(j) = ""

            Next

            For j = 0 To x - 1

                If (Char.IsLetterOrDigit(word(j))) Then

                    newword(y) = word(j)

                    y = y + 1

                End If

            Next

            parser(i) = newword

            If parser(i).Substring(0, 2) = "CD" Or parser(i).Substring(0, 2) = "00" Then

                lboTSMTape.Items.Add(parser(i))

            End If

        Next

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