Data base connectivity problem

If there are two forms 1) Main form 2) Sub Form

In the Main Form there is a button which leads to the sub Form
The Sub form has got some database connectivity in that..
Do i have to create the connection in the main form or is it fine if I create it in the sub Form cuz Im getting security exceptions.

Can someone please help me out??? I appreicate ur help in advance

Actually Im having a problem with the database connectivity it says:

An unhandled exception of type 'System.Security.SecurityException' occurred in Sample.exe

Can any1 help me out???

Are you connection to local or remote database ? Is it password-protected ?

btw , it's gonna be more convenient to declare the connection obj in a module so it can be accessed from anywhere in your proj .

Create a seperate database component which can be called from anywhere in the program.
Pass your stored proc and parameters in to return a datareader object or a dataset object (or a collection - what ever you want!).

I am using MS-Access and the database is not remote itz local database.

You may want to post some code for more help.

You should create a class that wraps all data access to that database (or any database). that way as far as your project code goes you are working with an object and not data access code directly. this will make your project much easier to modify and maintain as well.


basic connection code (this is for an Informix database):

declared at class level

Private _cnWMS As OleDb.OleDbConnection

in public sub new() or wherever you want

try
_cnWMS = New OleDb.OleDbConnection("Provider=Ifxoledbc.2;Password=pw;Persist Security Info=True;User ID=userID;Data Source=viaware@conwaywdsoc")

_cnWMS.open

<blah blah data access happens here>
catch ex as exception
throw new exception ("Error in whatever your function or sub was",ex)
finally
_cnWMS.close
end try

VB Code:

Public Class Form1
    Inherits System.Windows.Forms.Form
 
#Region " Windows Form Designer generated code "
 
    Public Sub New()
        MyBase.New()
 
        'This call is required by the Windows Form Designer.
        InitializeComponent()
 
        'Add any initialization after the InitializeComponent() call
 
    End Sub
 
    'Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub
 
    'Required by the Windows Form Designer
    Private components As System.ComponentModel.IContainer
 
    'NOTE: The following procedure is required by the Windows Form Designer
    'It can be modified using the Windows Form Designer.  
    'Do not modify it using the code editor.
    Friend WithEvents lblFirstName As System.Windows.Forms.Label
    Friend WithEvents lblLastName As System.Windows.Forms.Label
    Friend WithEvents lblAddress As System.Windows.Forms.Label
    Friend WithEvents txtFirstName As System.Windows.Forms.TextBox
    Friend WithEvents txtLastName As System.Windows.Forms.TextBox
    Friend WithEvents txtAddress As System.Windows.Forms.TextBox
    Friend WithEvents btnSubmit As System.Windows.Forms.Button
    Friend WithEvents odbconSam As System.Data.OleDb.OleDbConnection
    Friend WithEvents odbdaSample As System.Data.OleDb.OleDbDataAdapter
    Friend WithEvents DsSample1 As Sample.dsSample
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.lblFirstName = New System.Windows.Forms.Label()
        Me.lblLastName = New System.Windows.Forms.Label()
        Me.lblAddress = New System.Windows.Forms.Label()
        Me.txtFirstName = New System.Windows.Forms.TextBox()
        Me.txtLastName = New System.Windows.Forms.TextBox()
        Me.txtAddress = New System.Windows.Forms.TextBox()
        Me.btnSubmit = New System.Windows.Forms.Button()
        Me.odbconSam = New System.Data.OleDb.OleDbConnection()
        Me.odbdaSample = New System.Data.OleDb.OleDbDataAdapter()
        Me.DsSample1 = New Sample.dsSample()
        CType(Me.DsSample1, System.ComponentModel.ISupportInitialize).BeginInit()
        Me.SuspendLayout()
        '
        'lblFirstName
        '
        Me.lblFirstName.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle
        Me.lblFirstName.Location = New System.Drawing.Point(72, 32)
        Me.lblFirstName.Name = "lblFirstName"
        Me.lblFirstName.Size = New System.Drawing.Size(104, 32)
        Me.lblFirstName.TabIndex = 0
        Me.lblFirstName.Text = "FirstName"
        '
        'lblLastName
        '
        Me.lblLastName.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle
        Me.lblLastName.Location = New System.Drawing.Point(72, 80)
        Me.lblLastName.Name = "lblLastName"
        Me.lblLastName.Size = New System.Drawing.Size(104, 32)
        Me.lblLastName.TabIndex = 1
        Me.lblLastName.Text = "LastName"
        '
        'lblAddress
        '
        Me.lblAddress.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle
        Me.lblAddress.Location = New System.Drawing.Point(72, 128)
        Me.lblAddress.Name = "lblAddress"
        Me.lblAddress.Size = New System.Drawing.Size(104, 32)
        Me.lblAddress.TabIndex = 2
        Me.lblAddress.Text = "Address:"
        '
        'txtFirstName
        '
        Me.txtFirstName.Location = New System.Drawing.Point(200, 32)
        Me.txtFirstName.Multiline = True
        Me.txtFirstName.Name = "txtFirstName"
        Me.txtFirstName.Size = New System.Drawing.Size(112, 32)
        Me.txtFirstName.TabIndex = 3
        Me.txtFirstName.Text = ""
        '
        'txtLastName
        '
        Me.txtLastName.Location = New System.Drawing.Point(200, 80)
        Me.txtLastName.Multiline = True
        Me.txtLastName.Name = "txtLastName"
        Me.txtLastName.Size = New System.Drawing.Size(112, 32)
        Me.txtLastName.TabIndex = 4
        Me.txtLastName.Text = ""
        '
        'txtAddress
        '
        Me.txtAddress.Location = New System.Drawing.Point(200, 128)
        Me.txtAddress.Multiline = True
        Me.txtAddress.Name = "txtAddress"
        Me.txtAddress.Size = New System.Drawing.Size(112, 32)
        Me.txtAddress.TabIndex = 5
        Me.txtAddress.Text = ""
        '
        'btnSubmit
        '
        Me.btnSubmit.Location = New System.Drawing.Point(72, 200)
        Me.btnSubmit.Name = "btnSubmit"
        Me.btnSubmit.Size = New System.Drawing.Size(112, 40)
        Me.btnSubmit.TabIndex = 6
        Me.btnSubmit.Text = "Submit"
        '
        'odbconSam
        '
        Me.odbconSam.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Password="""";User ID=Admin;Data Source=Z:\course\" & _
        "Chapter.04\Data\sample.mdb;Mode=Share Deny None;Extended Properties="""";Jet OLEDB" & _
        ":System database="""";Jet OLEDB:Registry Path="""";Jet OLEDB:Database Password="""";Je" & _
        "t OLEDB:Engine Type=5;Jet OLEDB:Database Locking Mode=1;Jet OLEDB:Global Partial" & _
        " Bulk Ops=2;Jet OLEDB:Global Bulk Transactions=1;Jet OLEDB:New Database Password" & _
        "="""";Jet OLEDB:Create System Database=False;Jet OLEDB:Encrypt Database=False;Jet " & _
        "OLEDB:Don't Copy Locale on Compact=False;Jet OLEDB:Compact Without Replica Repai" & _
        "r=False;Jet OLEDB:SFP=False"
        '
        'odbdaSample
        '
        Me.odbdaSample.TableMappings.AddRange(New System.Data.Common.DataTableMapping() {New System.Data.Common.DataTableMapping("Table", "tblSample", New System.Data.Common.DataColumnMapping() {New System.Data.Common.DataColumnMapping("fldAddress", "fldAddress"), New System.Data.Common.DataColumnMapping("fldFirstName", "fldFirstName"), New System.Data.Common.DataColumnMapping("fldLastName", "fldLastName")})})
        '
        'DsSample1
        '
        Me.DsSample1.DataSetName = "dsSample"
        Me.DsSample1.Locale = New System.Globalization.CultureInfo("en-US")
        Me.DsSample1.Namespace = "http://www.tempuri.org/dsSample.xsd"
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(584, 469)
        Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.btnSubmit, Me.txtAddress, Me.txtLastName, Me.txtFirstName, Me.lblAddress, Me.lblLastName, Me.lblFirstName})
        Me.Name = "Form1"
        Me.Text = "Form1"
        CType(Me.DsSample1, System.ComponentModel.ISupportInitialize).EndInit()
        Me.ResumeLayout(False)
 
    End Sub
 
#End Region
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim pbndTemp As Binding, pintRecords As Integer
        pintRecords = odbdaSample.Fill(DsSample1)
 
        pbndTemp = New Binding("Text", DsSample1, "tblSample.fldFirstName")
        txtFirstName.DataBindings.Add(pbndTemp)
 
        pbndTemp = New Binding("Text", DsSample1, "tblSample.fldLastName")
        txtLastName.DataBindings.Add(pbndTemp)
 
        pbndTemp = New Binding("Text", DsSample1, "tblSample.Address")
        txtAddress.DataBindings.Add(pbndTemp)
    End Sub
End Class

First, I would lose the data object controls and work with them in pure code.

second, what line is your error being thrown?

third, databinding like that is evil. Pure evil.

Finally, always always always always use a try catch block around all code. this way you can get the stacktraces and error messages when something bad happens.

What are you trying to accomplish? If I could get a copy of that database and what the requirements are I could put something together for you. If you are interested, send me a private message and we can arrange it.

It gives error at INITIALIZECOMPONENT() saying that system.security.securityexception error occured

Thanx a lot mike it did work I appreciate ur help man

turns out his database was on a network share. This is why he was getting a security exception. Either set Intranet to full trust of move the database to the local machine and its all good.