How to write data to a file in Visual Studios? - visual-studio-2010

Question

I'm writing a program that reads an input file that contains a line:
Scott Atchison,200,74
The file contains around 30 different lines of data. I know how to read in the file. After the file is read in it is split and then a calculation needs to be done (I know how to do that).
However, the problem that I have is the output file, I can get only the last line of the input file to the output file. This is what I have right now:
Public Class BMI
Dim data As String
Dim strName As String
Dim intWeight As Integer
Dim intHeight As Integer
Dim decBMI As Decimal
Private Sub btnInputFile_Click(sender As System.Object, e As System.EventArgs) Handles btnOpenFile.Click
'User chooses a file
OpenFile.ShowDialog()
'Choose a file name into a label
lblFileInput.Text = OpenFile.FileName
Dim inputFile As New IO.StreamReader(lblFileInput.Text)
Do While (inputFile.Peek() > -1)
data = inputFile.ReadLine
Dim fields() As String = data.Split(",")
strName = fields(0)
intWeight = fields(1)
intHeight = fields(2)
txtData.Text = txtData.Text & data & vbNewLine
Loop
FileClose()
End Sub
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles btnSaveFile.Click
SaveFile.ShowDialog()
lblFileOutput.Text = SaveFile.FileName
Dim output As IO.StreamWriter
output = New IO.StreamWriter(lblFileOutput.Text)
output.WriteLine(data)
End Sub
Private Sub Button1_Click_1(sender As System.Object, e As System.EventArgs) Handles Button1.Click
decBMI = (intWeight * 703 / (intHeight ^ 2))
data = strName & ", " & decBMI
End Sub
End Class
Wouldn't it write a line until all 30 lines are read, or Am I missing something, like a while loop? Any help would be appreciated.

Answer 1

It would be nice if you gave us a nice, executable, snippet of code, including declarations of all your variables. For instance, where is "data" defined. What is the relationship between both chunks of code? Are they in the same procedure?
The first thing I notice is that you are splitting each line, "data", into fields, saving them into variables, which you just ignore. You then append "data" to a text box.
Assuming that "data" is shared between the two chunks of code, then reason for your problem is that the value being written to the streamwriter is the last value of "data", which happens to be the last line that was read into it.