Using LINQ to create a simple login
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JDWebs
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Published on 2012-07-07T19:30:36Z
Indexed on
2012/07/07
21:16 UTC
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I'm an C# ASP.NET beginner, so please excuse anything that's... not quite right!
In short, I want to create a really basic login system: one which runs through a database and uses sessions so that only logged in users can access certain pages. I know how to do most of that, but I'm stuck with querying data with LINQ on the login page.
On the login page, I have a DropDownList to select a username, a Textbox to type in a password and a button to login (I also have a literal for errors). The DropDownList is databound to a datatable called DT_Test. DT_Test contains three columns: UsernameID (int), Username (nchar(30)) and Password (nchar(30)). UsernameID is the primary key.
I want to make the button's click event query data from the database with the DropDownList and Textbox, in order to check if the username and password match. But I don't know how to do this...
Current Code (not a lot!):
Front End:
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Login_Test.aspx.cs" Inherits="Login_Login_Test" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Login Test</title>
</head>
<body>
<form id="LoginTest" runat="server">
<div>
<asp:DropDownList ID="DDL_Username" runat="server" Height="20px"
DataTextField="txt">
</asp:DropDownList>
<br />
<asp:TextBox ID="TB_Password" runat="server" TextMode="Password"></asp:TextBox>
<br />
<asp:Button ID="B_Login" runat="server" onclick="B_Login_Click" Text="Login" />
<br />
<asp:Literal ID="LI_Result" runat="server"></asp:Literal>
</div>
</form>
</body>
</html>
Back End:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
public partial class Login_Login_Test : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
Binder();
}
}
private void Binder()
{
using (DataClassesDataContext db = new DataClassesDataContext())
{
DDL_Username.DataSource = from x in db.DT_Honeys select new { x.UsernameID, txt = x.Username };
DDL_Username.DataBind();
}
}
protected void B_Login_Click(object sender, EventArgs e)
{
if (TB_Password.Text != "")
{
using (DataClassesDataContext db = new DataClassesDataContext())
{
}
}
}
}
I have spent hours searching and trying different code, but none of it seems to fit in for this context.
Anyway, help and tips appreciated, thank you very much!
- I am aware of security risks etc. but this is not a live website or anything, it is simply for testing purposes as a beginner. *
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