VB.NET Connection string ADODB Connection (Web.Config) - asp.net

Question

I write the code below to connect database using web config but cannot connect database using ADODB to fetch data from database into textboxes
Webconfig
<connectionStrings>
<clear />
<add name="constr" connectionString="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|CustomerInfor.mdb" providerName="System.Data.OleDb"/>
</connectionStrings>
SearchButton
Dim consString As String = System.Configuration.ConfigurationManager.ConnectionStrings("constr").ConnectionString
Dim objConn As New OleDbConnection(consString)
objConn.Open()
Please help with right code to fetch data from database into textboxes
Thanks

Answer 1

Ok, lets try this a bit different.
First up: Lets get the connection string OUT side of the code.
Like for desktop, or anything else? You can add values like connection string to the project like this:
And really nice is you get to use the connection builder to do this.
The above setting are shoved into web.config for you automatic.
So, setup your connection in above.
Ok, now in this case, I just shove on the screen a few text boxes for a user and hotel name.
Real plane jane like this:
<div style="width:25%;text-align:right;padding:25px;border:solid;border-width:1px">
<style> .tbox {width:260px;margin-left:5px;margin-bottom:15px;border-radius:8px;border-width:1px}</style>
Hotel Name: <asp:TextBox ID="txtHotelName" runat="server" class="tbox"/>
<br />
First Name: <asp:TextBox ID="txtFirst" runat="server" class="tbox" />
<br />
Last Name:<asp:TextBox ID="txtLast" runat="server" class="tbox"/>
<br />
City: <asp:TextBox ID="txtCity" runat="server" class="tbox"/>
<br />
Active:<asp:CheckBox ID="ckActive" runat="server" />
<br />
<br />
Ok, now our code to load this. I don't have a text box or source for the id, but a integer value OR a text value will work.
So, our code to load up is this:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not IsPostBack Then
LoadData()
End If
End Sub
Sub LoadData()
Dim cmdSQL As OleDbCommand = New OleDbCommand()
cmdSQL.CommandText = "SELECT * from tblhotels where ID = #ID"
cmdSQL.Parameters.Add("#ID", OleDbType.Integer).Value = 23
Dim rst As DataTable = MyRst(cmdSQL)
With rst.Rows(0)
txtHotelName.Text = .Item("HotelName")
txtFirst.Text = .Item("FirstName")
txtLast.Text = .Item("LastName")
txtCity.Text = .Item("City")
ckActive.Checked = .Item("Active")
End With
ViewState("rst") = rst
End Sub
Note the cute helper routine MyRst.
So, you can use that routine EVERY where. eg:
Dim cmdSQL As OleDbCommand = New OleDbCommand("select * from RoomTypes")
Dim rst as DataTable = MyRst(cmdSQL)
So, it just a handy dandy routine. (you do NOT have to use parameters if you don't need them).
Ok, so we loaded the one row into the table (and we save that row for later use into ViewState)
Ok, so now we see this:
Now, the save code. Note how we used a record set (datatable) in place of a GAZILLION parameters.
We do this for quite a few reasons.
Strong data type conversion occurs here.
Parameter order for the save does not matter. I can cut-paste, or add 5 or 15 more columns here, and it works - and order does not matter!!!
So, now the save code.
Protected Sub cmdSave_Click(sender As Object, e As EventArgs) Handles cmdSave.Click
SaveData()
End Sub
Sub SaveData()
Dim rst As DataTable = ViewState("rst")
Using con As New OleDbConnection(My.Settings.AccessTest2)
Using cmdSQL As New OleDbCommand("SELECT * from tblHotels WHERE ID = 0", con)
Dim da As OleDbDataAdapter = New OleDbDataAdapter(cmdSQL)
Dim daSQLU As OleDbCommandBuilder = New OleDbCommandBuilder(da)
con.Open()
With rst.Rows(0)
.Item("HotelName") = txtHotelName.Text
.Item("FirstName") = txtFirst.Text
.Item("LastName") = txtLast.Text
.Item("City") = txtCity.Text
.Item("Active") = ckActive.Checked
End With
da.Update(rst)
End Using
End Using
End Sub
NOTE: not a bug, I MOST certainly did use where ID = 0
So, the nice part is we can add more text box etc. We will have to add code to setup the text boxes, but at least the order don't matter.
Last but not least?
That helper routine, the one I use to fill datatables. I even use it for say filling out combo box (dropdown lists), or whatever.
Public Function MyRst(cmdSQL As OleDbCommand) As DataTable
Dim rstData As New DataTable
Using MyCon As New OleDbConnection(My.Settings.AccessTest2)
cmdSQL.Connection = MyCon
MyCon.Open()
rstData.Load(cmdSQL.ExecuteReader)
End Using
Return rstData
End Function
So note how we used the connection string setting that we setup in the project.
And since access is sensitive to parameter order, then I adopted the above idea of using a data table. Note that this approach also works for a grid, or even adding rows. When you run that update routine? rows added, rows edits, row deleted?
They all are done for you with the ONE da.Upate(rst).
Note also, you should set your project to run as x86, and not x64, since JET ONLY can work as x32. However, the ACE data engine can be had for x64 bits.