Show message "You are already logged in" upon RE-login?

I am new to C# and building a login form,i want to show below message if user is already logged in and try to login again.

how to show message "You are already logged in" if user attempt to login again.

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Windows.Forms;

using System.Data.SqlClient;

namespace Login

{

public partial class LogIin : Form

{

public LogIin()

{

InitializeComponent();

}

private void LogIn_Click(object sender, EventArgs e)

{

SqlConnection con = new SqlConnection(@"Data Source=IBMPC\SQLEXPRESS;Initial Catalog=UserData;Integrated Security=True");

SqlCommand cmd = new SqlCommand("select * from User_Credential where UserName = @UserName and Passwords = @Passwords",con);

cmd.Parameters.AddWithValue("@UserName", UsTxt.Text);

cmd.Parameters.AddWithValue("@Passwords",PassTxt.Text);

SqlDataAdapter sda = new SqlDataAdapter(cmd);

DataTable dt = new DataTable();

sda.Fill(dt);

con.Open();

int i = cmd.ExecuteNonQuery();

con.Close();

if (dt.Rows.Count > 0)

{

Welcome_Form wf = new Welcome_Form();

wf.Show();

}

else

{

MessageBox.Show("Please enter Correct Username and Password");

}

private void Exit_Click(object sender, EventArgs e)

{

this.Close();

}

2 Replies

Know the answer? Post it — somebody with the same question will find it here.

Sanwar Ranwa7y ago
Accepted answer
Hello Inderjeet

IF you already login in then you prevent your application to redirect to login page ,when you logout then redirect it to Login Page This baisc business Logic so try to Implement it .
+1
Sreekanth Reddy7y ago
If already user already logged In, Why you are showing him the login page again ?
0