I am trying to create a Login page for asp.net - asp.net

Question

I am trying to reference a database with sql to compare it to the text boxes, I do not know why my code is not working, its probably my IF statement? It could be that I am not writing the SQL statement correctly also.
Protected Sub btnValidate_Click(sender As Object, e As EventArgs) Handles btnValidate.Click
Dim strSQL As String = "SELECT * FROM loginInfo"
If "SELECT UserName, PassCode From loginInfo Where [UserName] [PassCode]" Then
Response.Redirect("gridView.aspx")
End If
End Sub

Answer 1

A couple of things wrong here:
Your query syntax is incorrect.
You don't need to load all the users on page load. Just checking the entered username and password will do.
On a side note, use parameterised queries to avoid SQL Injection.
What you can do is this - in the btnValidate_Click method, get your entered username and password, pass it to the query and if you find a record with username and password matching the user entered text, consider it as a successful login and redirect to the required page. Code would be something like this:
Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load
End Sub
Protected Sub btnValidate_Click(sender As Object, e As EventArgs) Handles btnValidate.Click
Dim recordMatch as int
Using con As New OleDbConnection( _
"Provider=Microsoft.Jet.OLEDB.4.0; Data Source=" + Server.MapPath("DynamicDataBase.mdb")),
con.Open()
Dim strSQL As String = "SELECT COUNT(1) FROM loginInfo WHERE [UserName] = #username AND [PassCode] = #passcode"
Dim cmd As New OleDbCommand(strSQL, con)
cmd.Parameters.Add("#username", SqlDbType.VarChar, 50).Value = yourusernametextbox.Text
cmd.Parameters.Add("#passcode", SqlDbType.VarChar, 50).Value = yourpasscodetextbox.Text
recordMatch = Convert.ToInt32(cmd.ExecuteScalar())
End Using
If recordMatch = 1 Then
Response.Redirect("gridView.aspx")
End If
End Sub