Question Passing dataset to database tables

[firchild]

Hi guys,

Having a bit of a problem here, mainly as I'm trying to keep the code simple as I'm teaching it to kids.. I've linked an Access database and a VB form, and I'm editing the data in the dataset via code. Only thing is, I can't get the data to write back to the table in access... It may be cause it's late, or I'm just stupid! But I hope someone would be able to take a look at the code, and suggest how to write back to the DB. Also posted it on YouTube (without the writing back to db bit, but if you look at the bottom of the code, you can see my pathetic effort to write it back to the data adapter in the vain hope it'll update the database!)

Here's the link to the vid: YouTube - 5.10 Adding and Deleting Data in Access through Visual Basic (1)

And here's my code

 Imports System.Data.OleDb
Public Class Form1
    Dim connectString As String = "Provider = Microsoft.JetOLEDB.4.0;" & "Data Source = HospitalDetails.mdb"

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        OleDbDataAdapter1.Fill(DsPatientsAndWards1)
        txtWardName.DataBindings.Add("Text", DsPatientsAndWards1, "Patients.Ward Name")
        txtWardClass.DataBindings.Add("Text", DsPatientsAndWards1, "Patients.Ward Class")
    End Sub

    Private Sub btnPrevious_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnPrevious.Click
        BindingContext(DsPatientsAndWards1, "Patients").Position = BindingContext(DsPatientsAndWards1, "Patients").Position - 1
    End Sub

    Private Sub btnNext_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnNext.Click
        BindingContext(DsPatientsAndWards1, "Patients").Position = BindingContext(DsPatientsAndWards1, "Patients").Position + 1
    End Sub

    Private Sub btnNew_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnNew.Click
        BindingContext(DsPatientsAndWards1, "Patients").AddNew()
    End Sub


    Private Sub btnDelete_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDelete.Click
        BindingContext(DsPatientsAndWards1, "Patients").RemoveAt(BindingContext(DsPatientsAndWards1, "Patients").Position)
        MsgBox("Message Deleted")
     End Sub

 Private Sub btnUpdate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnUpdate.Click
        OleDbDataAdapter1.Update(DsPatientsAndWards1)
        MsgBox("Record Updated")
     End Sub

    
End Class

Any help would be greatly appreciated, but as I stated, I'm trying to keep it simple.. (i.e. using adapters rather than SQL)

 

[jmcilhinney]

What value does Update return? If it's not zero then data is being saved. In that case, you're just looking for it in the wrong place or at the wrong time. To learn how local data files are managed, follow the first link in my signature.

 

[firchild]

It returns nothing, even when I run a trace.

 

[jmcilhinney]

When you say that it returns nothing, do you actually mean that it returns zero?

 

[firchild]

Nope, it's null.

 

[JohnH]

Nope, it's null.

It is not possible for a function that returns an Integer value to return Nothing.