connect to database placed in another program

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;
using System.Data.Sql;

namespace PC
{
    class DataBase
    {
        public static Boolean AddTodo(string name, string email, string password)
        {
            Boolean c = false;

            try
            {
                SqlConnection connection = new SqlConnection();
                connection.ConnectionString = @"Data Source=localhost;Initial Catalog=DataBaseWin;Integrated Security=SSPI";
                //Data Source=D:\max\مشروع التخرج\New Code\ServerWin\ServerWin\DataBaseWin.sdf
                connection.Open();

                SqlCommand command1 = new SqlCommand("SELECT * FROM UserInfo.  WHERE UserName= @UserName", connection);
                command1.Parameters.Add(new SqlParameter("@UserName", name));
                command1.ExecuteNonQuery();

                SqlDataReader reader = command1.ExecuteReader();
                {
                    if (!reader.HasRows)
                    {
                        reader.Close();

                        SqlCommand command = new SqlCommand("insert into UserInfo. (UserName, UserEmail, Password) values (@UserName, @UserEmail, @Password)", connection);
                        command.Parameters.Add(new SqlParameter("@UserName", name));
                        command.Parameters.Add(new SqlParameter("@UserEmail", email));
                        command.Parameters.Add(new SqlParameter("@Password", password));

                        command.ExecuteNonQuery();
                        c = true;
                    }
                    else
                    {
                        MessageBox.Show("UserName is thaken");
                    }
                }
                connection.Close();
            }
            catch (SqlException e)
            {
                MessageBox.Show(e.Message);
            }
            return c ;
        }


        public static Boolean Signin(string name, string password)
        {
            Boolean c = false;

            try
            {

                SqlConnection connection = new SqlConnection();
                connection.ConnectionString = @"Data Source=localhost;Initial Catalog=DataBaseWin;Integrated Security=SSPI";
                
                connection.Open();

                SqlCommand command1 = new SqlCommand("SELECT * FROM UserInfo.  WHERE UserName= @UserName AND Password= @Password ", connection);
                command1.Parameters.Add(new SqlParameter("@UserName", name));
                command1.Parameters.Add(new SqlParameter("@Password", password));
                command1.ExecuteNonQuery();

                SqlDataReader reader = command1.ExecuteReader();
                {
                    if (!reader.HasRows)
                    {
                        reader.Close();
                        c = true;
                    }
                    else
                    {
                        MessageBox.Show("Your UserName OR Password Not Right");
                    }
                }
                connection.Close();
            }
            catch (SqlException e)
            {
                MessageBox.Show(e.Message);
            }
            return c;
        }
    }
}