Solved

The ConnectionString property has not been initialized. Why

Posted on 2012-03-20
2
244 Views
Last Modified: 2012-03-20
The ConnectionString property has not been initialized. This error comes when one entry is being done. i.e on second entry.

Imports System
Imports System.Data
Imports System.Data.SqlClient


Public Class NewUsernamepasswords
    Dim con As New SqlConnection
    Dim da As SqlDataAdapter
    Dim ds As DataSet
    Dim dt As DataTable
    Dim s As String
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

       
        ' Delete any existing record.
        Dim query As String
        Dim cmd As New SqlCommand
        query = "DELETE FROM accounts WHERE UserName='" & TextBox1.Text & "'"
        cmd = New SqlCommand(query, con)
        con.Open()
        cmd.ExecuteNonQuery()

        ' Insert the new record.
        query = "INSERT INTO accounts(username,password) VALUES ('" & TextBox1.Text & "', '" & HashPassword(TextBox2.Text) & "')"
        cmd = New SqlCommand(query, con)
        cmd.ExecuteNonQuery()

        ' Close the connection.
        con.Close()
        con.Dispose()
        query = ""

        MessageBox.Show("Ok")
    End Sub


    Private Sub NewUsernamepasswords_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        con = New SqlConnection("server=ADMIN-PC\SQLEXPRESS;database=testadms;Integrated security=true")
    End Sub
    Private Function HashPassword(ByVal password As String) As String
        Dim hash As String = ""
        Dim i As Integer
        For i = 0 To password.Length - 1
            hash &= Chr(Asc(password.Substring(i, 1)) + 1)
        Next i
        Return hash
    End Function
End Class
0
Comment
Question by:searchsanjaysharma
2 Comments
 
LVL 29

Accepted Solution

by:
Paul Jackson earned 500 total points
ID: 37741826
You dispose of the con object at the end of  Button1_Click, therby destroying the connection and the connection string.
Better to move the initialisation of the con object within  Button1_Click rather than in  NewUsernamepasswords_Load.

 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

         Dim con As New SqlConnection
         con = New SqlConnection("server=ADMIN-PC\SQLEXPRESS;database=testadms;Integrated security=true")

        ' Delete any existing record.
        Dim query As String
        Dim cmd As New SqlCommand
        query = "DELETE FROM accounts WHERE UserName='" & TextBox1.Text & "'"
        cmd = New SqlCommand(query, con)
        con.Open()
        cmd.ExecuteNonQuery()

        ' Insert the new record.
        query = "INSERT INTO accounts(username,password) VALUES ('" & TextBox1.Text & "', '" & HashPassword(TextBox2.Text) & "')"
        cmd = New SqlCommand(query, con)
        cmd.ExecuteNonQuery()

        ' Close the connection.
        con.Close()
        con.Dispose()
        query = ""

        MessageBox.Show("Ok")
    End Sub

Open in new window

0
 

Author Closing Comment

by:searchsanjaysharma
ID: 37745821
ok
0

Featured Post

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Microsoft Reports are based on a report definition, which is an XML file that describes data and layout for the report, with a different extension. You can create a client-side report definition language (*.rdlc) file with Visual Studio, and build g…
If you need to start windows update installation remotely or as a scheduled task you will find this very helpful.
Although Jacob Bernoulli (1654-1705) has been credited as the creator of "Binomial Distribution Table", Gottfried Leibniz (1646-1716) did his dissertation on the subject in 1666; Leibniz you may recall is the co-inventor of "Calculus" and beat Isaac…
I've attached the XLSM Excel spreadsheet I used in the video and also text files containing the macros used below. https://filedb.experts-exchange.com/incoming/2017/03_w12/1151775/Permutations.txt https://filedb.experts-exchange.com/incoming/201…

726 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question