Public Class Form4
Dim objcon As New OleDbConnection
Dim strSQL As String
Dim strconnection As String = "provider=microsoft.ACE.OLEDO.12.0;Data Source=shweta:\WindowsApplication1\Databaseapp.accdb"
Dim da As New OleDbDataAdapter
Dim ds As New DataSet
Dim attempt As Integer = 0
Private Sub btnsignin_Click(sender As Object, e As EventArgs) Handles btnsignin.Click
Dim strName = txtpassword.Text
Dim strpass = txtpassword.Text
With objcon
.Close()
If .State = ConnectionState.Closed Then
.ConnectionString = strconnection
.Open()
'{they r showing An unhandled exception of type
'System.InvalidOperationException' occurred in
' System.Data.dll }}
MsgBox("connectionstate.open", MsgBoxStyle.Information, "connected")
End If
End With
ds.Clear()
strSQL = "Select * from logintable where username='" & Txtusername.Text & "' And password =''" & txtpassword.Text '"
da = New OleDbDataAdapter(strSQL, objcon)
da.Fill(ds, "logintable")
If ds.Tables("logintable").Rows.Count <> 0 Then
MaximizeBox = True
MinimizeBox = True
Else
MaximizeBox = False
MinimizeBox = False
MessageBox.Show("invalid")
End If
Form2.Show()
Me.Hide()
End Sub
End Class
Here are errors fixed:
It works if could put Imports System.Data.OleDb before Public Class Form4.
Also, add Public Property Form2 As Object inside form4 block.
Still some part of code is missing. Could you please specify them?
Related
I'm doing a simple login page for Visual Basic connected to an access database and I keep receiving this error when I run the project.
I would greatly appreciate it if anyone could help me resolve this.
Imports System.Data.OleDb
Public Class frmLogin
Dim objConnection As New OleDb.OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=Login.accdb")
Dim objDA As New OleDb.OleDbDataAdapter("SELECT * FROM User", objConnection)
Dim objCB As New OleDb.OleDbCommandBuilder(objDA)
Dim objDS As New DataSet()
Public Username, Password As String
Dim UserFound As Boolean
Private Sub frmLogin_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Retrieve()
End Sub
Private Sub btnLogin_Click(sender As Object, e As EventArgs) Handles btnLogin.Click
Username = txtUser.Text
Password = txtPassword.Text
For i As Integer = 1 To (objDS.Tables("User").Rows.Count)
If CStr(objDS.Tables("User").Rows(i - 1).Item("Username")) =
Username And
CStr(objDS.Tables("User").Rows(i - 1).Item("Password")) = Password Then
UserFound = True
Me.Hide()
MessageBox.Show("Welcome to the System!")
frmStudents.Show()
Exit For
End If
txtUser.Text = String.Empty
txtPassword.Text = String.Empty
Next
If UserFound = False Then
MessageBox.Show("Access Denied")
End If
End Sub
Private Sub Retrieve()
objDS.Clear()
objDA.FillSchema(objDS, SchemaType.Source, "User")
objDA.Fill(objDS, "User")
End Sub
End Class
The error occurs in this line:
objDA.FillSchema(objDS, SchemaType.Source, "User") "User" is
underlined in the error
This is further info on the error shown:
An unhandled exception of type 'System.InvalidCastException' occurred
in Microsoft.VisualBasic.dll Additional information: Conversion from
string "User" to type 'Integer' is not valid
Instead of hauling down the entire users table just to verify a user get the count of records that match. Of course, in a real application, you would never store password as plain text.
Private Sub VerifyUser()
Dim objConnection As New OleDb.OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0; Data Source=Login.accdb")
Dim cmd As New OleDbCommand("Select Count(*) From Users Where [Username] = #Username and [Passwor] = #Password;", objConnection)
cmd.Parameters.Add("#Username", OleDbType.VarChar).Value = txtUsername.Text
cmd.Parameters.Add("#Password", OleDbType.VarChar).Value = txtPassword.Test
objConnection.Open()
Dim count As Integer = CInt(cmd.ExecuteScalar())
Dim message As String = ""
If count > 0 Then
message = "Welcome"
Else
message = "Sorry"
End If
MessageBox.Show(message)
End Sub
How i can hide delete.button and change it with another button with warning that you only have 1 operation manager you cannot delete again. when i have only one (Position= Operation manager) in my datagridview
Imports System.Data.OleDb
Public Class Form5
Dim conn As New OleDbConnection
Dim comm As New OleDbCommand
Dim dr As OleDbDataReader
Dim query As String
Private Sub Form5_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Me.LogInTableAdapter.Fill(Me.LogInDataSet.LogIn)
If conn.State = ConnectionState.Open Then conn.Close()
conn.ConnectionString = "Provider = Microsoft.ACE.OLEDB.12.0; " & _
"Data Source = C:\Users\69neers\Desktop\Database\Program\Program\bin\Debug\LogIn.accdb; " & _
"Persist Security Info=false"
conn.Open()
query = "SELECT * FROM LogIn WHERE Uname = '" & UnameTextBox.Text & "'"
comm.CommandText = query
comm.Connection = conn
dr = comm.ExecuteReader
dr.Read()
If LogInBindingSource.Count = 1 And dr("Pos") = PosComboBox.Text Then
btndelete.Enabled = False
btndelete.Hide()
btndelalter.Show()
btndelete.Enabled = False
Else
btndelete.Enabled = True
btndelalter.Hide()
btndelete.Show()
End If
dr.Close()
End Sub
I am trying to create a forgot password screen for my application. I am using the tab control for the different pages. My current code is able to create a user but it is able to create duplicates (Which is an issue needed to be rectified) I then have an issue with the forget password screen not working completely.
My code is:
Imports System.Data.OleDb
Public Class Form2
Dim connection As New OleDb.OleDbConnection
Dim dbProvider As String
Dim dbSource As String
Dim MyDocumentsFolder As String
Dim TheDatabase As String
Dim FullDatabasePath As String
Dim ds As New DataSet
Dim da As OleDb.OleDbDataAdapter
Dim sql As String
Dim DBTest1 As String
Dim DBTestP1 As String
Dim cmd As New OleDbCommand(sql, connection)
Dim connStr As String
Dim usernamevalid As Integer
Dim passwordvalid As Integer
Public Sub Button1_Click_1(sender As Object, e As EventArgs) Handles Button1.Click
If User.Text.Length < 4 Then
usernamevalid = 0
ElseIf User.Text.Length > 4 Then
usernamevalid = 1
End If
If Pass.Text.Length < 5 Then
passwordvalid = 0
ElseIf Pass.Text.Length > 5 Then
passwordvalid = 1
End If
If usernamevalid = 0 Then
MsgBox("Username Must Be At Least 5 Characters")
End If
If passwordvalid = 0 Then
MsgBox("Password Must Be At Least 5 Characters")
End If
If passwordvalid And usernamevalid = 1 And Pass.Text = RePass.Text Then
dbProvider = "Provider=Microsoft.ACE.OLEDB.12.0;"
dbSource = "Data Source = C:\Users\Daniel\Documents\Robocopy.accdb"
Dim connStr = dbProvider & dbSource
DBTest1 = User.Text
DBTestP1 = Pass.Text
sql = "INSERT INTO Robocopy(username,[password],sq,sqa) VALUES('" & DBTest1 & "','" & DBTestP1 & "','" & SQREG.Text & "', '" & SQAREG.Text & "')"
Using connection = New OleDb.OleDbConnection(connStr)
Using cmd = New OleDb.OleDbCommand(sql, connection)
connection.Open()
cmd.ExecuteNonQuery()
connection.Close()
MsgBox("User Created!")
'With cmd.Parameters
'.AddWithValue("usernamer", DBTest.Text)
'.AddWithValue("password", DBTestP.Text)
'.AddWithValue("email", txtsub.text)
'.AddWithValue("contactnum", txtau.text)
'End With
'cmd.ExecuteNonQuery()
End Using
End Using
ElseIf Not Pass.Text = RePass.Text Then
MsgBox("Passwords did not match")
End If
End Sub
Private Sub Button2_Click_1(sender As Object, e As EventArgs) Handles Button2.Click
Dim result = MessageBox.Show(" Are you sure you want to quit", "Are you sure?", MessageBoxButtons.YesNoCancel)
Me.Close()
End Sub
Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
If NewPass.Text = ReNewPass.Text Then
Try
connection.Open()
cmd = New OleDbCommand("update robocopy set [password] = '" & NewPass.Text & "' where username = '" & UserFGT.Text & "'", connection)
cmd.ExecuteNonQuery()
MessageBox.Show("PASSWORD CHANGE SUCCESSFULLY")
connection.Close()
Catch ex As Exception
MsgBox(ex.Message)
End Try
End If
End Sub
End Class
The exception it catches is The ConnectionString property has not been initialized
Currently I changed my code to what I think you mean:
Button4's code has been changed as such:
Private Sub ResetPassword_Click(sender As Object, e As EventArgs) Handles ResetPassword.Click
If NewPass.Text = ReNewPass.Text Then
Using connection = New OleDb.OleDbConnection(connStr)
Using cmd = New OleDb.OleDbCommand(sql, connection)
connection.Open()
cmd = New OleDbCommand("update robocopy set [password] = '" & NewPass.Text & "' where username = '" & UserFGT.Text & "'", connection)
cmd.ExecuteNonQuery()
MessageBox.Show("PASSWORD CHANGE SUCCESSFULLY")
connection.Close()
End Using
End Using
End If
End Sub
I now get the error for cmd = New OleDbCommand("update robocopy set [password] = '" & NewPass.Text & "' where username = '" & UserFGT.Text & "'", connection)
I am getting the error for cmd where it says 'Read Only' Variable cannot be the target of assignment
The only thing I can see wrong with the connection string are extra spaces after 'Data Source='.
Here's an example from connectionstrings.com:
Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\myFolder\myAccessFile.accdb;Persist Security Info=False;
This is my first question, by the way - and I'm not sure exactly how to ask, or say what's wrong. There's 3 things I can't sort so any help would be appreciated.
Module:
This and the first (login) form work as they are but I couldn't get either Form to reference con.connectionstring for them to use without having to re-use the string contained in "" (as they do below) - my attempts ended up with errors including saying that the state couldn't be changed as the connection was already open, but I'd like the same one string to be referenced from the Forms.
Module ConnectionModule
Public con As OleDb.OleDbConnection = New OleDb.OleDbConnection
Public da As OleDb.OleDbDataAdapter
Public ds As DataSet = New DataSet
Public Path As String = Application.StartupPath
Public Sub OpenDb()
con.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0; Data Source=F:\Computing A2\CG4 Coursework\Greener Cleaning\dbCoursework.accdb"
con.Open()
If con.State = ConnectionState.Closed Then
MsgBox("Connection to db not made.")
End If
End Sub
Public CurrentUser As String = Nothing
End Module
The First Form:
Public Class LoginForm
Private Sub LoginForm_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
OpenDb()
con.Close()
End Sub
Private Sub btnLogin_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLogin.Click
Dim ID As String = txtID.Text
Dim Pass As String = txtPassword.Text
If IsNumeric(ID) = False Or ID.Length > 4 Or Pass = Nothing Then
MsgBox("Staff ID is a 4-digit number and Password must not be blank.")
Else
Dim con As New System.Data.OleDb.OleDbConnection()
OpenDb()
con.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0; Data Source=F:\Computing A2\CG4 Coursework\Greener Cleaning\dbCoursework.accdb"
Try
Dim sql As String = "SELECT * FROM tblStaff WHERE [StaffID]='" & ID & "' AND [Pword] = '" & Pass & "'"
Dim sqlCom As New System.Data.OleDb.OleDbCommand(sql)
'Open Database Connection
sqlCom.Connection = con
con.Open()
Dim sqlRead As System.Data.OleDb.OleDbDataReader = sqlCom.ExecuteReader()
If sqlRead.Read() Then 'Correct:
MenuForm.Show()
Me.Hide()
CurrentUser = ID
Else 'Incorrect:
MsgBox("Staff ID or Password incorrect.")
txtPassword.Text = ""
txtID.Text = ""
txtID.Focus()
End If
Catch ex As Exception
MsgBox("Database Connection Error.")
End Try
con.Close()
End If
End Sub
End Class
A form to change the password:
The problem here is that lblUser (A clarification for the user to tell them which password will be changed) only outputs the data already within the program as a variable: CurrentUser (as assigned upon successful login). No error is produced but the full name of the user isn't shown (or possibly read from the database).
I'm also unsure how the UPDATE SQL command should be contained within the second procedure, btnAccept_click, here. What the syntax is, basically. I haven't found a clear example to look at.
Imports System.Data.OleDb
Public Class PasswordForm
Private Sub PasswordForm_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
con = New System.Data.OleDb.OleDbConnection()
con.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0; Data Source=F:\Computing A2\CG4 Coursework\Greener Cleaning\dbCoursework.accdb"
Dim Returned(2) As String
CurrentUser = CurrentUser
Dim cmd As OleDbCommand = New OleDbCommand("SELECT [Title], [Forename], [Surname] FROM tblStaff WHERE [StaffID]='" & CurrentUser & "'", con)
Try
con.Open()
Dim reader As OleDbDataReader = cmd.ExecuteReader()
If reader.HasRows Then
reader.Read()
'Makes db contents variables
Returned(0) = reader.Item("[Title]").ToString
Returned(1) = reader.Item("[Forename]").ToString
Returned(2) = reader.Item("[Surname]").ToString
End If
reader.Close()
Catch ex As Exception
Me.Hide()
MsgBox("Database Connection Error.")
Finally
con.Close()
End Try
lblUser.Text = "Current User: " & CurrentUser & Returned(0) & Returned(1) & Returned(2)
''Only outputs CurrentUser
End Sub
Private Sub btnAccept_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAccept.Click
Dim Current As String = txtCurrent.text
Dim NewPass As String = txtNew.Text
'Verification
If txtNew.Text = txtConfirm.Text And NewPass.Length <= 20 Then
Dim cmd As OleDbCommand = New OleDbCommand("UPDATE tblStaff SET [Pword]='" & NewPass & "' WHERE [StaffID]='" & CurrentUser & "'", con)
End If
End Sub
End Class
Thank you, again, for anyone with ideas (especially exact code).
Oh and throughout what's here there are no errors thrown. Just missing content.
you are opening the connection in openDB() and you are trying to open it again in form1, this will throw the error you are getting. So comment all the con related lines in your form. Same comment for your passowrd form also.
'Dim con As New System.Data.OleDb.OleDbConnection()
OpenDb()
'con.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0; Data Source=F:\Computing A2\CG4 Coursework\Greener Cleaning\dbCoursework.accdb"
Try
Dim sql As String = "SELECT * FROM tblStaff WHERE [StaffID]='" & ID & "' AND [Pword] = '" & Pass & "'"
Dim sqlCom As New System.Data.OleDb.OleDbCommand(sql)
'Open Database Connection
sqlCom.Connection = con
'con.Open()
...
end try
I'm creating a login form for vb.net using ms access 2003 as database. But it only checks for the username and bypasses the password. Meaning that if the username is correct and the password doesn't jive with the username, the user can still enter the system. Here is my code:
Try
Dim NoAcc As String
Dim NoAccmod2 As String
Dim NoPas As String
Dim cn As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\db1.mdb;Jet OLEDB:Database Password=nrew123$%^;")
Dim cmd As OleDbCommand = New OleDbCommand("Select * from admintable where AdminName= '" & TextBox4.Text & "' ", cn)
cn.Open()
rdr = cmd.ExecuteReader
If rdr.HasRows Then
rdr.Read()
NoAcc = rdr("AdminName")
NoPas = rdr("AdminPass")
If (TextBox4.Text = NoAcc And TextBox3.Text = NoPas) Then NoAccmod2 = NoAcc
adminview.Show()
Me.Hide()
Else
MsgBox("Incorrect Username/Password")
TextBox4.Clear()
TextBox3.Clear()
End If
Catch
MsgBox("Error logging in, please try again", MsgBoxStyle.Exclamation)
End Try
How do I do it so that it checks both username and password?
You are using a single line IF .. THEN :
If (TextBox4.Text = NoAcc And TextBox3.Text = NoPas) Then NoAccmod2 = NoAcc
so the next line will always be executed:
adminview.Show()
you have to rearrange your IF .. THEN conditions
I will share about login system in vb.net using binding navigator that less of coding. just following the link below!
http://www.tesear.com/2011/09/login-system-in-vbnet.html
You could have BOTH the uname and pword in the database and "WHERE" on both, if you get no record back, then you have your answer.
Try using System.String.Compare(String str1,String str2, Boolean ) As Integer like:
If (System.String.Compare(TextBox4.Text, NoAcc, false) And System.String.Compare(TextBox3.Text, NoPas, false)) Then NoAccmod2 = NoAcc
here is the code:
Imports System.Data
Imports System.Data.OleDb
Public Class Form5
Inherits System.Windows.Forms.Form
Dim mypath = Application.StartupPath & "\login.mdb"
Dim mypassword = ""
Dim conn As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & mypath & ";Jet OLEDB:Database Password=" & mypassword)
Dim cmd As OleDbCommand
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Me.Hide()
Dim sql = "SELECT UserID ,PassID FROM MYTAB WHERE USERID='" & TextBox1.Text & "' AND PASSID='" & TextBox2.Text & "'"
cmd = New OleDbCommand(sql, conn)
conn.Open()
Dim dr As OleDbDataReader = cmd.ExecuteReader
Try
If dr.Read = False Then
MessageBox.Show("Authentication failed...")
Me.Show()
Else
MessageBox.Show("Login successfully...")
Dim frmDialogue As New Form11
frmDialogue.ShowDialog()
End If
Catch ex As Exception
MsgBox(ex.Message)
End Try
conn.Close()
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
Close()
End Sub
Private Sub LinkLabel1_LinkClicked(ByVal sender As System.Object, ByVal e As System.Windows.Forms.LinkLabelLinkClickedEventArgs) Handles LinkLabel1.LinkClicked
Me.Hide()
Dim frmDialogue As New Form1
frmDialogue.ShowDialog()
End Sub
Private Sub Form5_Closing(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles MyBase.Closing
Dim frm As New Form1
frm.Show()
End Sub
End Class
Try
Dim NoAcc As String
Dim NoPas As String
Dim rdr As OleDbDataReader
Dim cnn As New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=D:\mobilestore.accdb;Persist Security Info=False;")
Dim cmd As OleDbCommand = New OleDbCommand("Select * from logindata where Username= '" & TextBox1.Text & "' and password='" & TextBox2.Text & "'", cnn)
'NoAcc = TextBox1.Text
'NoPas = TextBox2.Text
cnn.Open()
rdr = cmd.ExecuteReader
If (rdr.Read()) Then
NoAcc = rdr("Username")
NoPas = rdr("password")
If (TextBox1.Text = NoAcc And TextBox2.Text = NoPas) Then
Adminpage.Show()
Me.Hide()
Else
MsgBox("Incorrect Username/Password")
TextBox1.Clear()
TextBox2.Clear()
End If
End If
Catch
MsgBox("Error logging in, please try again", MsgBoxStyle.Exclamation)
End Try
End Sub