CODEWITHSUNDEEP
vb.netvisual-studio-2010
user2201924
user2201924

Reputation: 11

“The ConnectionString property has not been initialized” error in VB.NET

Every time I tried to connect to the database it give me this error "The ConnectionString property has not been initialized"

How can i avoid this error and make it work?

Here are my codes:

Imports System.Data.OleDb
Public Class frmLoginPage
Dim con As New OleDbConnection
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    Dim dt As New DataTable
    Dim ds As New DataSet
    ds.Tables.Add(dt)
    Dim da As New OleDbDataAdapter

    da = New OleDbDataAdapter("Select*from tblPassword", con)
    da.Fill(dt)

    Dim newRow As DataRow = dt.NewRow
    With newRow
        If .Item("Username") = txtUsername.Text And .Item("Password") = txtPassword.Text Then frmMainMenu.ShowDialog() Else MsgBox("The username or password you entered was incorrect, please try again!", MsgBoxStyle.Critical, "Information")
    End With
End Sub

Upvotes: 1

Views: 10882

Answers (3)

Panda1122
Panda1122

Reputation: 121

You never assigned your connection string to the connection object, just like the error is saying.

Insert a line setting the connection string before con.open.

Con.connectionstring = connection Con.Open() Or better yet, change your using statement as follows

Dim Connection As String = "Data Source=.\SQLEXPRESS;AttachDbFilename=G:\VB Project\Library Catalog System\Library Catalog System\library.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True"

Using Con As New SqlConnection(connection)

Upvotes: 1

SMHasnain
SMHasnain

Reputation: 706

This Problem Occurs when you donot consider making a new connection The solution is very simple, all you have to do is to make

Dim conString as string = "Your connection string here"

Dim con As new OleDbConnection
con.connectionSting= ConSting
con.open()
      'now simply write the query you want to be executed


'At the end write
con.close()

this will solve your problem. if it doesn't solve your problem post reply I will try to solve it.

Upvotes: 1

DeanOC
DeanOC

Reputation: 7262

You have instantiated an OleDbConnection object, but you haven't set the connectionstring property so it doesn't know where it should connect to. You also haven't opened it. Your code should look something like:

Dim myConnection As OleDbConnection = New OleDbConnection()
myConnection.ConnectionString = myConnectionString
myConnection.Open()
' execute queries, etc
myConnection.Close()

Upvotes: 2

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