VB.NET中的数据库访问

Question

I have accessed a database in VB.NET using the following code:

Public Class Form1
    Private Sub btnLoad_Click(ByVal sender As System.Object, _
      ByVal e As System.EventArgs) Handles btnLoad.Click
        Dim con As OleDb.OleDbConnection = New OleDb.OleDbConnection
        Dim dbProvider As String
        Dim dbSource As String
        Dim ds As New DataSet
        Dim da As OleDb.OleDbDataAdapter
        Dim sql As String

        dbProvider = "PROVIDER=Microsoft.Jet.OLEDB.4.0;"
        dbSource = "Data Source = AddressBook.mdb"
        con.ConnectionString = dbProvider & dbSource
        con.Open()
        sql = "SELECT * FROM tblContacts"
        da = New OleDb.OleDbDataAdapter(sql, con)
        da.Fill(ds, "Address Book")
        MsgBox("Database Open")
        con.Close()
        MsgBox("Database Closed")
        txtFirstName.Text = ds.Tables("AddressBook").Rows(0).Item(1)
        txtSurname.Text = ds.Tables("AddressBook").Rows(0).Item(2)
    End Sub
End Class  

However in line "txtFirstName.Text = ds.Tables("AddressBook").Rows(0).Item(1)", it gives me an exception saying that an instance of an object should be created. I am not understanding what exactly the problem is. How can I create an instance, and of WHAT should I create an instance?

Answer 1

You used a space in

da.Fill(ds, "Address Book") 

But no space in

txtFirstName.Text = ds.Tables("AddressBook").Rows(0).Item(1)

For the name of the table. Therefore a table with name "AddressBook" does not exist.