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7.0

VS 2005 Windows Forms VB Amending data with OLEDB DataAdapter and DataSet. Error: Object reference not set to an instance of an object.

Asked by FJRMill in Visual Studio, VB Objects, Microsoft Visual Basic.Net

Tags: Visual Basic (Visual Studio 2005, Windows Forms), Object reference not set to an instance of an object.

Hi Experts..

In VS 2005, VB Windows Forms project, I have filled a dataSet from an oledb dataAdapter.

(there is only one row of dummy data in the Access test table)
I want to edit a single field and save it back to the database.

Please see the attached code snippet

I have (supposedly) set the connection, initialised the DataAdapter, and filled the Dataset.
However, When the executing code moves to set the Dataset row for editing, it's generating error:
'Object reference is not set to an instance of an object'
(see attached jpg)

{FYI I'm learning .Net VB and have copied this model from book:
VS.NET: The .NET Framework Black Book. }

It seems simple enough .. but I can't figure what is causing this error. Please could someone help out?

Many thanks

Mill

View the Solution FREE for 30 Days

         
           
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             Dim constr As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\my.mdb"
        Dim con1 As New OleDbConnection(constr)
        Dim ds As New DataSet()
        Dim da As OleDb.OleDbDataAdapter
        Dim strSQL As String = "SELECT * FROM MyTable" 
 
        con1.Open()
 
 
        'Initialise the DataAdapter with a connection and a query
        da = New OleDb.OleDbDataAdapter(strSQL, con1)
 
        Dim SQLBuilder As OleDb.OleDbCommandBuilder = _
                       New OleDb.OleDbCommandBuilder(da)
 
 
 
        'Use the dataAdapter to fill the Dataset
        da.Fill(ds)
 
        'amend field and save the record
 
     ** Error in line below this **   
        ds.Tables("MyTable").Rows(0).BeginEdit()
 
        ds.Tables("MyTable").Rows(0)("MyField") = MyStringVariable.ToString
        ds.AcceptChanges() 
 
        ' write back to the database
        da.Update(ds)

           
         

Attachments:

error.JPG (31 KB) (File Type Details)

The error message

20091111-EE-VQP-92 / EE_QW_2_20070628

VS 2005 Windows Forms VB Amending data with OLEDB DataAdapter and DataSet. Error: Object reference not set to an instance of an object.

Asked by FJRMill in Visual Studio, VB Objects, Microsoft Visual Basic.Net

Tags: Visual Basic (Visual Studio 2005, Windows Forms), Object reference not set to an instance of an object.

About this solution