Imports System.Data.OleDb
Public Class LoginForm1

Private Sub OK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles OK.Click
            Dim con As New OleDbConnection("Provider=Microsoft.jet.oledb.4.0;data source=C:\Users\Documents\VodStore\VodStore\bin\Debug\VodStock.mdb")
        Dim cmd As OleDbCommand = New OleDbCommand("SELECT * FROM Users WHERE userid = '" & UsernameTextBox.Text & "' AND password = '" & PasswordTextBox.Text & "' ", con)
        Dim sdr As OleDbDataReader = cmd.ExecuteReader()
        ' If the record can be queried, Pass verification and open another form.   
        If (sdr.Read() = True) Then
            MessageBox.Show("Access Granted!")
            MessageBox.Show("Access Denied! Invalid username or password.")
        End If
    Catch es As Exception
    End Try
End Sub

Private Sub Cancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Cancel.Click
End Sub

End Class

Here i got the problem of "Data type mismatch in criteria expression.". Please help me...

To answer your question, we need to know:

  1. What is the table definition for Users?
  2. What values are in UserNameTextBox.Text and PasswordTextBox.Text?

It would also help (you just as much as us) to look at the final SQL query string in cmd.CommandText.

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