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"
DbCon.Open()
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
Contacts.Show()
Me.Close()
Else
UsernameTextBox.Clear()
PasswordTextBox.Clear()
MessageBox.Show("Invalid Username or Password")
UsernameTextBox.Focus()
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
Me.Close()
Else
End If
End Sub