Can't add new record to access database

[woodhousecomp]

Hi, as part of a computing project I am writing a program to add, edit and delete data from an access database.

I have successfully written code to edit data but when adding a row to the dataset I run into a problem.

This is the code in my button which adds a new record.

Dim cb As New OleDb.OleDbCommandBuilder(da)
        Dim NewRow As DataRow
        NewRow = ds.Tables("CandidateID").NewRow

        NewRow.Item(0) = TxtCandidateID.Text
        NewRow.Item(1) = TxtFirstName.Text
        NewRow.Item(2) = TxtSecondName.Text
        NewRow.Item(3) = TxtHospital.Text
        NewRow.Item(4) = TxtPosistionHeld.Text
        NewRow.Item(5) = TxtOTPhysio.Text
        NewRow.Item(6) = TxtNoYearsInHands.Text
        NewRow.Item(7) = TxtSpeciality.Text
        NewRow.Item(8) = TxtBAHTNo.Text
        NewRow.Item(9) = TxtAddressOfHospital.Text
        NewRow.Item(10) = TxtAddressForCorrespondance.Text
        NewRow.Item(11) = TxtTelHome.Text
        NewRow.Item(12) = TxtTelWork.Text
        NewRow.Item(13) = TxtFax.Text
        NewRow.Item(14) = TxtEmail.Text
        NewRow.Item(15) = TxtReceipt.Text
        NewRow.Item(16) = TxtInvoice.Text
        NewRow.Item(17) = TxtDietaryNeeds.Text
        NewRow.Item(18) = TxtPhysicalLearningNeeds.Text

        ds.Tables("CandidateID").Rows.Add(NewRow)

        da.Update(ds, "CandidateID")

        MsgBox("New record added")

These are my global declarations:

Dim con As New OleDb.OleDbConnection
    Dim ds As New DataSet
    Dim da As OleDb.OleDbDataAdapter
    Dim sql As String = "SELECT * FROM TblCandidate"

When I click the button I ge the error message : Object reference not set to an instance of an object.
The line "NewRow = ds.Tables("CandidateID").NewRow" is highlighted.

Can anyone help?
Thanks in advance.

Joe

[kleinma]

Where are you ever loading a table into your dataset?

Dim ds as New DataSet creates a new dataset object, but it has no tables in it based on the code I see that you posted. So when you try to access the CandidateID table, which does not exist in the dataset, you get the null reference exception thrown.

[woodhousecomp]

O yeah sorry I forgot to post it.

I fill it in form load

 Private Sub FrmCandidate_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        con.ConnectionString = "PROVIDER=Microsoft.Jet.OLEDB.4.0;Data Source = C:\Joe coursework\NESDatabase.mdb"
        con.Open()
        da = New OleDb.OleDbDataAdapter(sql, con)
        da.Fill(ds, "TblCandidate")
        con.Close()
        ReloadText()
    End Sub

[woodhousecomp]

I figured out what was wrong.
I had written CandidateID instead of TblCandidate.
Thanks for the quick reply