以登录形式创建Windows身份验证和SQL Server身份验证

Question

I have a login form in Visual Studio C# and below is a screenshot of it.

https://i.stack.imgur.com/uziUD.png

My goal is to allow the user to choose whether to log in using Windows authentication, in a workplace as we are using LAN network or using SQL Server authentication (username and password are stored in server -> security -> login).

Below is the code so far:

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;
using System.Data.Sql;
using System.Data.OleDb;

namespace Login_HouseKeeping_
{
    public partial class Form1: Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        // Connection string
        string cs = @"Data Source = 172.28.40.19\CASINO2008R2; Initial catalog =GCVS2_DEV_GHR; Integrated Security = True;";

        // Login click event
        private void button1_Click(object sender, EventArgs e)
        {
            if (textBox1.Text == "" || textBox2.Text == "")
            {
                MessageBox.Show("Please provide Username and Password");
                return;
            }
            else
                try
                {
                    //Create sqlconnection
                    SqlConnection con = new SqlConnection(cs);

                    SqlCommand cmd = new SqlCommand(@"SELECT * FROM Logins WHERE Username = @username AND Password = @Password", con);

                    cmd.Parameters.AddWithValue("@username", textBox1.Text);
                    cmd.Parameters.AddWithValue("@Password", textBox2.Text);

                    con.Open();

                    SqlDataAdapter adapt = new SqlDataAdapter(cmd);
                    DataSet ds = new DataSet();
                    adapt.Fill(ds);

                    con.Close();

                    int count = ds.Tables[0].Rows.Count;

                    // if count equals to 1, then show frmMain form
                    if (count == 1)
                    {
                        MessageBox.Show("Login successful");
                        this.Hide();

                        frmMain fm = new frmMain();
                        fm.Show();
                    }
                    else
                    {
                         MessageBox.Show("Login failed");
                    }
               }
               catch (Exception ex)
               {
                   MessageBox.Show(ex.Message);
               }
        }

        private void textBox2_TextChanged(object sender, EventArgs e)
        {
            textBox2.PasswordChar = '*';
        }

        private void btn_Exit_Click(object sender, EventArgs e)
        {
            this.Close();
        }
    }
}

I can't seem to find many resources on implementing these two authentication into my login. How do I achieve this?

EDIT:

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void label2_Click(object sender, EventArgs e)
        {

        }

        private void btn_Exit_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void btn_Login_Click(object sender, EventArgs e)
        {



            var connStrBldr = new System.Data.SqlClient.SqlConnectionStringBuilder();
            connStrBldr.DataSource = "172.28.40.19\CASINO2008R2";
            connStrBldr.InitialCatalog = "GCVS2_DEV_GHR";
            if (WindowsAuth)
            {
                connStrBldr.IntegratedSecurity = true;
            }
            else
            {
                connStrBldr.IntegratedSecurity = false;
                connStrBldr.UserID = textBox1.Text;
                connStrBldr.Password = textBox2.Text;
            }
            using (SqlConnection con = new SqlConnection(connStrBldr.ToString()))
            {
                con.Open();
                //do your lookup on login here
            }







        }

        private void WindowsAuth_CheckedChanged(object sender, EventArgs e)
        {

        }

        private void SqlAuth_CheckedChanged(object sender, EventArgs e)
        {

        }
    }
}

Answer 1

Authentication is controlled by your connection string. Your best bet is to use System.Data.SqlClient.SqlConnectionStringBuilder to build the connection string dynamically based on whether you want SQL Server auth or Windows auth:

var connStrBldr = new System.Data.SqlClient.SqlConnectionStringBuilder();
connStrBldr.DataSource = "172.28.40.19\CASINO2008R2";
connStrBldr.InitialCatalog = "GCVS2_DEV_GHR";
if (useWindowsAuth) {
    connStrBldr.IntegratedSecurity = true;
} else {
    connStrBldr.IntegratedSecurity = false;
    connStrBldr.UserID = textBox1.Text;
    connStrBldr.Password = textBox2.Text;
}
using (SqlConnection con = new SqlConnection(connStrBldr.ToString())) {
    con.Open();
    //do your lookup on login here
}

Answer 2

I'm only posting this answer since OP can't seem to make @Tim's answer work. Credits to @Tim.

Just simply use:

EDIT: Changed since username and password is not mandatory for windows authentication.

private void btn_Login_Click(object sender, EventArgs e)
{
    bool useWindowsAuth = WindowsAuth.Checked; // Assuming that WindowsAuth is your radio button

    string userName = string.Empty;
    string password = string.Empty;

    if(!useWindowsAuth)
    {
        userName = textBox1.Text;
        password = textBox2.Text;

        if (string.IsNullOrWhiteSpace(userName) || string.IsNullOrWhiteSpace(password))
        {
            MessageBox.Show("Please provide Username and Password");
            return;
        }
    }

    var connStrBldr = new System.Data.SqlClient.SqlConnectionStringBuilder();
    connStrBldr.DataSource = @"172.28.40.19\CASINO2008R2";
    connStrBldr.InitialCatalog = "GCVS2_DEV_GHR";

    if (useWindowsAuth) 
    {
        connStrBldr.IntegratedSecurity = true;
    } 
    else 
    {
        connStrBldr.IntegratedSecurity = false;
        connStrBldr.UserID = userName;
        connStrBldr.Password = password;
    }

    bool validUser = true;

    try
    {
        using (SqlConnection con = new SqlConnection(connStrBldr.ToString())) 
        {
            con.Open();
            //do your lookup on login here
        }
    }
    catch(SqlException) // An exception will be caught if invalid credentials were used.
    {
        validUser = false;
    }

    if(validUser)
        MessageBox.Show("Login successful!");
    else
        MessageBox.Show("Login failed!");    
    }
}

I have verified that the code works using a sample project. You just have to make sure of the following:

1. Username and Password is correct (Server > Security).
2. User has access to GCVS2_DEV_GHR table. This can be configured under (Server > Security > User)

Also, this way of coding is not a good way to do it but since you seem new to C# just make sure to study more about good practices.