Hola hola, si usas Login1_Authenticate es mucho mas sencillo hacer lo que buscas.
Código VB:
Ver original' previousConnectionState = conn.State
Try
Dim strSQL As String
strSQL = "SELECT * FROM USUARIOS WHERE USUARIO='" & Login1.UserName & "' AND CONTRASEÑA='" & Login1.Password & "'"
Dim com As New SqlClient.SqlCommand(strSQL, conn)
Dim reader As SqlClient.SqlDataReader
conn.Open()
reader = com.ExecuteReader
If Not reader.Read Then
conn.Close()
Else
conn.Close()
Session("usuario") = Login1.UserName
Session("contraseña") = Login1.Password
Response.Redirect("inicio.aspx")
End If
Catch ex As Exception
Login1.FailureText = "Error: " & ex.Message
End Try