Create New Table Row Error

[thekoolgeek]

The following program, reads a text file, and adds it to the database; by creating a new table and records for it.
 
However, I have a problem at the end, where I get the error when the compiler executes "ct.NewRow.AcceptChanges()"
 
Any help would be appreciated, thanks.
 
 
Private Sub btnUpload_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnUpload.Click
        Dim AllText As String = "", LineOfText As String = ""
        OpenFormDialog.Filter = "Text files (*.TXT)|*.TXT" 'Display only Text Files
        OpenFormDialog.ShowDialog() 'Display Dialog Boz
        If OpenFormDialog.FileName <> "" Then
            Try 'open file and catch any errors
                FileOpen(1, OpenFormDialog.FileName, OpenMode.Input)
                Dim conn As New RECORDSDataSet
                Dim tablename = 1
                Dim ct As DataTable = conn.Tables.Add(tablename)
 
                ct.Columns.Add("CustomerNumber", GetType(Int16))
                ct.Columns.Add("CustomerName", GetType(String))
                ct.Columns.Add("MeterNumber", GetType(String))
                ct.Columns.Add("PreviousMonth", GetType(Double))
                ct.Columns.Add("Owed", GetType(Double))
                ct.Columns.Add("Paid", GetType(Double))
                ct.Columns.Add("CurrentMonth", GetType(Double))
 
                Do Until EOF(1) 'Read lines from file, stop when it reaches the end
                    LineOfText = LineInput(1)
                    'add each line to the AllText variable
                    Call CreateDatabase(LineOfText, conn, ct)
                Loop
            Catch
                MsgBox("Error Opening File") 'Display message box if file cannot be opened
            Finally
                FileClose(1) 'close file
            End Try
        End If
    End Sub
 
    Sub CreateDatabase(ByVal LineOfText As String, ByRef conn As RECORDSDataSet, ByRef ct As DataTable)
        'Variables that will be required for input into the database
        Dim arr() As String = Split(LineOfText, " ")
        Dim CustomerNumber, LastMonth, CurrentHours As Integer
        Dim Owed, Paid As Double
        Dim CustomerName, MeterNumber As String
 
        CustomerNumber = arr(0)
        CustomerName = arr(1) & arr(2) 'Combine first and last name
        MeterNumber = arr(3)
        LastMonth = arr(4)
        Owed = arr(5)
        Paid = arr(6)
        CurrentHours = arr(7)
 
        'Adds new row
        ct.NewRow.BeginEdit()
        ct.NewRow.Item(0) = CustomerNumber
        ct.NewRow.Item(1) = CustomerName
        ct.NewRow.Item(2) = MeterNumber
        ct.NewRow.Item(3) = LastMonth
        ct.NewRow.Item(4) = Owed
        ct.NewRow.Item(5) = Paid
        ct.NewRow.Item(6) = CurrentHours
        'PROBLEM HERE, in STEP INTO MODE, THIS IS WHERE THE ERROR IS CAUGHT
        ct.NewRow.AcceptChanges()
        ct.NewRow.EndEdit()
    End Sub
End Class

[jmcilhinney]

Firstly, I believe that you've already been told not to call AcceptChanges in a previous thread.

Secondly, NewRow is NOT a property. It is a function that creates a new row and returns it. That means that every time you call NewRow it creates a new row. You're calling it 10 times so you're creating 10 rows. Also, you never keep a reference to any of those rows and add it to the table. Create a single new row, assign it to a variable, set its fields, do NOT call AcceptChanges, then finally add the row to the table that created it.

Finally, that FileOpen/LineInput/FileClose is an old method of I/O that should never be used in new code. You should use members of the System.IO namespace, e.g. StreamReader, for .NET I/O operations.

[thekoolgeek]

Firstly, I believe that you've already been told not to call AcceptChanges in a previous thread.

Secondly, NewRow is NOT a property. It is a function that creates a new row and returns it. That means that every time you call NewRow it creates a new row. You're calling it 10 times so you're creating 10 rows. Also, you never keep a reference to any of those rows and add it to the table. Create a single new row, assign it to a variable, set its fields, do NOT call AcceptChanges, then finally add the row to the table that created it.

Finally, that FileOpen/LineInput/FileClose is an old method of I/O that should never be used in new code. You should use members of the System.IO namespace, e.g. StreamReader, for .NET I/O operations.

First of all, I've never been told that.
Secondly, ok.
And finally, thats how I learned it from my Visual Basic 2005 Programmer's Reference book. It works and you know what they say "if it ain't broken, don't fix it."

[jmcilhinney]

Firstly, sorry, my mistake. Must have been someone else asking a very similar question.

Secondly, cool.

Thirdly, that's extremely dodgy. Anyone writing a VB 2005 reference book should be shot for including code like that. Microsoft explicitly state that that form of I/O is included for legacy support and may degrade performance. It's only there to support upgraded VB6 apps and should never be used in new code.

[thekoolgeek]

Firstly, I believe that you've already been told not to call AcceptChanges in a previous thread.

Secondly, NewRow is NOT a property. It is a function that creates a new row and returns it. That means that every time you call NewRow it creates a new row. You're calling it 10 times so you're creating 10 rows. Also, you never keep a reference to any of those rows and add it to the table. Create a single new row, assign it to a variable, set its fields, do NOT call AcceptChanges, then finally add the row to the table that created it.

Finally, that FileOpen/LineInput/FileClose is an old method of I/O that should never be used in new code. You should use members of the System.IO namespace, e.g. StreamReader, for .NET I/O operations.

Now about step two here, can I get some code for that?

[jmcilhinney]

You already know how. How would you normally call a function and assign the result to a variable? You know how because you're already doing it, e.g.

Dim ct As DataTable = conn.Tables.Add(tablename)

You also know how set a field of a DataRow because you're already doing that too.

[thekoolgeek]

This is what I have:

Sub CreateDatabase(ByVal LineOfText As String, ByRef conn As RECORDSDataSet, ByVal ct As DataTable, ByVal FileName As String)
        'Variables that will be required for input into the database
        Dim arr() As String = Split(LineOfText, " ")
        Dim CustomerNumber, LastMonth, CurrentHours As Integer
        Dim Owed, Paid As Double
        Dim CustomerName, MeterNumber As String
        Dim NR As DataRow
 
        CustomerNumber = arr(0)
        CustomerName = arr(1) & arr(2) 'Combine first and last name
        MeterNumber = arr(3)
        LastMonth = arr(4)
        Owed = arr(5)
        Paid = arr(6)
        CurrentHours = arr(7)
 
        NR = conn.Tables(FileName).NewRow
 
        NR.BeginEdit()
        NR.Item(0) = CustomerNumber
        NR.Item(1) = CustomerName
        NR.Item(2) = MeterNumber
        NR.Item(3) = LastMonth
        NR.Item(4) = Owed
        NR.Item(5) = Paid
        NR.Item(6) = CurrentHours
        NR.EndEdit()
 
        conn.Tables(FileName).Rows.Add(NR)
 
    End Sub

Its giving me an error, so how would i fix it?

[jmcilhinney]

Its giving me an error, so how would i fix it?

How would we know if we don't know what the error is?

[thekoolgeek]

This is everything that I have. It is not returning any errors, but the Table is not getting created.

Imports System.Data
Imports System.Data.OleDb
 
 
Public Class frmMain
 
    'Images that will be used for buttons
    Dim btnBG As System.Drawing.Image = Image.FromFile("C:\Documents and Settings\Allan Hernandez\My Documents\Visual Studio 2005\Projects\E-Z Watt Electric Co\E-Z Watt Electric Co\btnbg.jpeg")
    Dim btnBG2 As System.Drawing.Image = Image.FromFile("C:\Documents and Settings\Allan Hernandez\My Documents\Visual Studio 2005\Projects\E-Z Watt Electric Co\E-Z Watt Electric Co\btnbg2.jpeg")
 
    Private Sub frmMain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'Change Button Backgrounds
        btnUpload.BackgroundImage = btnBG2
        btnReports.BackgroundImage = btnBG2
        btnExit.BackgroundImage = btnBG2
    End Sub
 
    Private Sub btnUpload_MouseHover(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnUpload.MouseHover
        'Change background when the mouse moves over the button.
        btnUpload.BackgroundImage = btnBG
        slMain.Text = "Upload a File for processing."
    End Sub
 
    Private Sub btnReports_MouseHover(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnReports.MouseHover
        'Change background when the mouse moves over the button.
        btnReports.BackgroundImage = btnBG
        slMain.Text = "Print/View Month's Reports"
    End Sub
 
    Private Sub btnExit_MouseHover(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnExit.MouseHover
        'Change background when the mouse moves over the button.        
        btnExit.BackgroundImage = btnBG
        slMain.Text = "Exit the application"
    End Sub
 
    Private Sub btnUpload_MouseLeave(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnUpload.MouseLeave
        'Change background when the mouse leaves the button.
        btnUpload.BackgroundImage = btnBG2
        slMain.Text = ""
    End Sub
 
    Private Sub btnReports_MouseLeave(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnReports.MouseLeave
        'Change background when the mouse leaves the button.
        btnReports.BackgroundImage = btnBG2
        slMain.Text = ""
    End Sub
 
    Private Sub btnExit_MouseLeave(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnExit.MouseLeave
        'Change background when the mouse leaves the button.
        btnExit.BackgroundImage = btnBG2
        slMain.Text = ""
    End Sub
 
    Private Sub btnExit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnExit.Click
        End
    End Sub
 
    Private Sub tmrTime_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles tmrTime.Tick
        'Aqcuires current date and time for label
        Dim CurrentDate As DateTime = DateTime.Now
 
        'Updates label with current Time, and Company Name
        lblTime.Text = "E-Z Watt Electric Co-Op: " & CurrentDate
    End Sub
 
    Private Sub btnUpload_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnUpload.Click
        Dim FileName As String = "", LineOfText As String = ""
        OpenFormDialog.Filter = "Text files (*.TXT)|*.TXT" 'Display only Text Files
        OpenFormDialog.ShowDialog() 'Display Dialog Boz
        If OpenFormDialog.FileName <> "" Then
            FileName = OpenFormDialog.FileName
            Try 'open file and catch any errors
                FileOpen(1, OpenFormDialog.FileName, OpenMode.Input)
                Dim conn As New RECORDSDataSet
                Dim tablename = 1
                Dim ct As DataTable = conn.Tables.Add(FileName)
 
                ct.Columns.Add("CustomerNumber", GetType(Integer))
                ct.Columns.Add("CustomerName", GetType(String))
                ct.Columns.Add("MeterNumber", GetType(String))
                ct.Columns.Add("PreviousMonth", GetType(Double))
                ct.Columns.Add("Owed", GetType(Double))
                ct.Columns.Add("Paid", GetType(Double))
                ct.Columns.Add("CurrentMonth", GetType(Double))
 
                Do Until EOF(1) 'Read lines from file, stop when it reaches the end
                    LineOfText = LineInput(1)
                    'add each line to the AllText variable
                    Call CreateDatabase(LineOfText, conn, ct, FileName)
                Loop
            Catch
                MsgBox("Error Opening File") 'Display message box if file cannot be opened
            Finally
                FileClose(1) 'close file
            End Try
        End If
    End Sub
 
    Sub CreateDatabase(ByVal LineOfText As String, ByRef conn As RECORDSDataSet, ByVal ct As DataTable, ByVal FileName As String)
        'Variables that will be required for input into the database
        Dim arr() As String = Split(LineOfText, " ")
        Dim CustomerNumber, LastMonth, CurrentHours As Integer
        Dim Owed, Paid As Double
        Dim CustomerName, MeterNumber As String
        Dim NR As DataRow
 
        CustomerNumber = arr(0)
        CustomerName = arr(1) & arr(2) 'Combine first and last name
        MeterNumber = arr(3)
        LastMonth = arr(4)
        Owed = arr(5)
        Paid = arr(6)
        CurrentHours = arr(7)
 
        NR = conn.Tables(FileName).NewRow
 
        NR.BeginEdit()
        NR.Item(0) = CustomerNumber
        NR.Item(1) = CustomerName
        NR.Item(2) = MeterNumber
        NR.Item(3) = LastMonth
        NR.Item(4) = Owed
        NR.Item(5) = Paid
        NR.Item(6) = CurrentHours
        NR.EndEdit()
 
        conn.Tables(FileName).Rows.Add(NR)
    End Sub
End Class

Any help would be appreciated.