Hi, I am creating an login page connected to a database. I am using access ODB. the problem is, if the user makes an wrong input, and the invalid data message box appeared, when typing the data again, and press ok, the following exeption occured:
Not allowed to change the 'ConnectionString' property. The connection's current state is open.

here is the code.

much needed help, thank you.

Public Class LoginForm1

    Dim DbCon As New OleDb.OleDbConnection
    Dim dbUp As New OleDb.OleDbCommand
    Dim Read As OleDb.OleDbDataReader

    Private Sub OK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles OK.Click
        DbCon.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|\unpw.mdb"
        dbUp.Connection = DbCon
        dbUp.CommandType = CommandType.Text
        dbUp.CommandText = "Select * from UNPW where Username=UsernameTextBox.Text and Password=PasswordTextBox.Text "
        dbUp.Parameters.Add("Username", Data.OleDb.OleDbType.Variant)
        dbUp.Parameters.Add("Password", Data.OleDb.OleDbType.Variant)
        dbUp.Parameters("Username").Value = UsernameTextBox.Text
        dbUp.Parameters("Password").Value = PasswordTextBox.Text
        Read = dbUp.ExecuteReader
        With Read
            If .Read Then

                MessageBox.Show("Invalid Username or Password")

            End If
        End With
    End Sub

    Private Sub Cancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Cancel.Click
        If MessageBox.Show("Do you want to exit?", "Exit", MessageBoxButtons.YesNo, MessageBoxIcon.Question) = Windows.Forms.DialogResult.Yes Then
        End If
    End Sub

Recommended Answers

All 3 Replies

close the database connection before end sub of OK.


{"COM object that has been separated from its underlying RCW cannot be used."}

Read = dbUp.ExecuteReader

i'm confused. it should work..

never mind. I made an work around. thank you.

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.