mdb & vb.net

  • Thread starter Thread starter RobinS
  • Start date Start date
OleDBConnection instantiated & configured
OleDBCommand (one for each DB operation you wish to perform) instantiated &
configured.
OleDBDataReader or DataSet instance for reading data
 
Have you tried to debug your code to see what is happening by place a break
point in Button1_Click event handler? What is the point to use
Try...Catch... but does nothing in Catch clause?

If you place a breakpoint there and hit F5, you can easily find out which
line of code throw you into Catch clause; furthermore, if you do something
in Catch... clause like this:

Try
....
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try

then from the exception message, you probably had already known what was
wrong before asking question here
 
VB 2003. This is what I wrote and it does not work;

Imports System.Data.OleDb

Public Class Form2
Inherits System.Windows.Forms.Form

Dim cn As OleDbConnection
Dim cmd As OleDbCommand
Dim dr As OleDbDataReader

'WINDOWS GENERATED

Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
OleDbDataAdapter1.Fill(DataSet11)
End Sub
Private Sub exitbutton_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles exitbutton.Click
Me.Close()
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click
Try
cn = New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0; Data
Source=C:\Documents and Settings\Name\Desktop\FillMe.mdb;")
'provider to be used when working with access database
cn.Open()
cmd = New OleDbCommand("select * from MainTable", cn)
dr = cmd.ExecuteReader
While dr.Read()
TextBox1.Text = dr(0)
TextBox2.Text = dr(1)
TextBox3.Text = dr(2)
'loading data into TextBoxes by column index
End While
Catch
End Try
dr.Close()
cn.Close()
End Sub
End Class

John said:
How do I input and retrieve data from tables in an .mdb file? I use vb.net
Click to expand...

I have a book by the way, and it only tells me how to create a data grid,
and display single records.
 
John,

Why are you using that reader, there is no need for that, that does the
DataAdapter.

So it can be.

Imports System.Data.OleDb

Public Class Form2
Inherits System.Windows.Forms.Form

Dim cn As OleDbConnection
Dim cmd As OleDbCommand
Click to expand...
'WINDOWS GENERATED
Click to expand...
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
dim ds as New Dataset
dim cn as
New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0; Data
Source=C:\Documents and Settings\Name\Desktop\FillMe.mdb;")

Dim da as New OleDbDataAdapter("select * from MainTable", cn)

da.Fill(ds)

Textbox1.DataBinding.Add("Text",ds.Table(0),"Col1")
Textbox2.DataBinding.Add("Text",ds.Table(0),"Col2")
Textbox3.DataBinding.Add("Text",ds.Table(0),"Col3")

End Sub

'Col1 is the first fieldname in your Jet database etc,

Done in this message so watch typos.

I hope this helps,

cor
 
Ah, I think Cor is being sarcastic. My most recent book does not really talk
about .MDB (JET/Access) databases at all but my previous book "ADO and
ADO.NET Examples and Best Practices" did.

--
____________________________________
William (Bill) Vaughn
Author, Mentor, Consultant
Microsoft MVP
INETA Speaker
www.betav.com/blog/billva
www.betav.com
Please reply only to the newsgroup so that others can benefit.
This posting is provided "AS IS" with no warranties, and confers no rights.
__________________________________
Visit www.hitchhikerguides.net to get more information on my latest book:
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and Hitchhiker's Guide to SQL Server 2005 Compact Edition (EBook)
 
Ok, so I created a connection from my .mdb file into my program using a
datagrid:

Dim ds As DataSet = New DataSet
DataGrid1.DataSource = DataSet11.DefaultViewManager

How do I input and retrieve data from tables in an .mdb file? I use vb.net
2003
 
John,

The questions you are asking do not have just one simple answer, nor are any
of the possible scenarios simple "couple of lines of code" solutions.

In general, you need Command objects to perform any C.R.U.D. (create, read,
update & delete) actions against your database. Now, that leaves you with 2
choices in ADO.NET:

Create & configure them yourself.
Use a DataAdapter & configure them that way.

Of course, you'll need a connection to the database that the command objects
can use....

And then you have to think about any return data from your CRUD actions,
that leaves you with
DataReaders
DataTables
DataSets

In short (too late!), it sounds like you need to take a look at the ADO.NET
objects more closely and begin to understand what each represents and how to
properly configure each.

Asking "how do I update my database" is actually a very vauge quesiton and
you shouldn't expect a meaningful response from such a quesiton.

Good luck.

Scott
 
Bill,

No I was not, as I have wrote often I don't read any book, Internet is my
main source especially MSDN in the case of dotNet. Beside that does my
general knowledge help me. I just refer to your knowledge I see in this
newsgroup. And I know you as somebody who was in past not so criticizing ADO
and DOA as some others did.

No sarcastic at all, it was truly meant.
(One day I will probably read your book all was it only because I am
curious, I write you soon why I did not accept your offer direct).

Cor
 
John,

If you were not multiposting in the way as you do but especially because you
are using Outlook Express crossposting it was much easier to help you.

Refering to my answer in another newsgroup where you have placed your
question takes to much time and makes my answer even more not understandable
for others who are searching than normally.

Cor
 
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