ReadFields() in TextFieldParser throwing exception - arrays

Question

I have a bunch of csv files in a folder. Here is a sample:
Item Value
Row1 Val1
Row2 Val2
Row3 Val3
Row4 Val4"
Row5 Val5
I had written a code to plot a chart based on the information available in all the csv file in that folder. Here is my button click event:
Private Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles generatePlot.Click
Dim dirs As FileInfo() = GetFilesInDirectory("*.csv", True) 'Get all the csv file from result folder in descending order (creation date)
Dim diNext As FileInfo
Try
For Each diNext In dirs.Reverse
Using MyReader As New FileIO.TextFieldParser(diNext.FullName)
MyReader.TextFieldType = FileIO.FieldType.Delimited
MyReader.SetDelimiters(",")
Dim currentRow As String()
While Not MyReader.EndOfData
currentRow = MyReader.ReadFields()
processRow(diNext, currentRow)
End While
End Using
Next
Catch ex As Exception
MessageBox.Show(ErrorToString)
End Try
'Save chart as an image
Chart1.SaveImage(imageSave, System.Drawing.Imaging.ImageFormat.Bmp)
End Sub
If you look at my sample csv, Row4 has a value of Val4". Note the double quote in it. And, I am getting an exception in my code at currentRow = MyReader.ReadFields() which says Line 5 cannot be parsed using the current delimiter. I know that the reason is because of the presence of double quote. Since this is a string array, I thought that I need to create a function to process each item in the array and trim out the double quote. But, I can't do it as the exception is thrown even before I can process the string array.
Any idea on how to solve this?
Hari

Answer 1

A StreamReader can be used to read text files, just look at the example below to achieve your needs:
Note that the MemoryStream and the Writer are not needed for you, just the Reader.
Public Sub ReadTest()
Using MemoryStream As New IO.MemoryStream()
Dim Writer As New IO.StreamWriter(MemoryStream) 'Writing on a memory stream to emulate a File
Writer.WriteLine("Item,Value")
Writer.WriteLine("Row1,Val1")
Writer.WriteLine("Row2,Val2")
Writer.WriteLine("Row3,Val3")
Writer.WriteLine("Row4,Val4""")
Writer.WriteLine("Row5,Val5")
Writer.Flush()
MemoryStream.Position = 0 'Reseting the MemoryStream to Begin Reading
Dim Reader As New IO.StreamReader(MemoryStream) 'Reading from the Memory but can be changed into the File Path
While Not Reader.EndOfStream
Dim Line As String = Reader.ReadLine
Dim Values() = Line.Split(",")
'Values(0) will contain the First Item
'Values(1) will contain the second Item
Values(1).Replace("""", "") 'Remove the quote from the value string
End While
End Using
End Sub

Answer 2

Thanks to the suggestion given by #jmcilhinney and #AugustoQ.
Private Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles generatePlot.Click
Dim dirs As FileInfo() = GetFilesInDirectory("*.csv", True) 'Get all the csv file from result folder in descending order (creation date)
Dim diNext As FileInfo
Dim currentRow As String()
Try
For Each diNext In dirs.Reverse
For Each rawRows As String In File.ReadLines(diNext.FullName)
currentRow = processRawRow(rawRows)
processRow(diNext, currentRow)
Next
Next
Catch ex As Exception
MessageBox.Show(ErrorToString)
End Try
'Save chart as an image
Chart1.SaveImage(imageSave, System.Drawing.Imaging.ImageFormat.Bmp)
End Sub
I had replaced the TextFieldParser completely and used this function:
Private Function processRawRow(ByVal rawRows As String) As String()
rawRows = rawRows.Replace("""", "").Trim()
Dim processedList = rawRows.Split(",")
Return processedList
End Function
And it works perfectly. Thanks everyone...
Hari