Needs combobox items having checkbox and multiple selection

Requirement : combobox having list of records (employee names) from database table say-'nworksuser' and list along with checkbox (for selection). Depending on selection(Multiple/Single/All) mode I need to display records in datagrid view from all related table(one to one / one to many).

Xaml :

<ComboBox Grid.Column="1" Grid.Row="3" Grid.ColumnSpan="2" Grid.RowSpan="2" Height="30" Name="comboBox_Employee"  > 

        </ComboBox>
        <DataGrid  Grid.Column="1" Grid.Row="5" Grid.ColumnSpan="11" Grid.RowSpan="15" Name="Datagrid_AttendanceLog"/>

.cs to fill combobox :

public partial class AttendanceLog : Window
    {
        string LiveUser;
        public AttendanceLog(string LiveUser)
        {
            InitializeComponent();
            this.LiveUser = LiveUser;
            FillComboEmpName();
        }
        void FillComboEmpName()
        {
            int eno;
            MySqlConnection conn4;
            conn4 = new MySqlConnection("server=localhost;uid=root;database=newcompanydatabase;pwd=Admin@123;");
            string Query = "select * from nWorksUser where _type='Employee' or _type='Admin_Employee';";
            MySqlCommand cmd2 = new MySqlCommand(Query, conn4);
            try
            {
                conn4.Open();
                MySqlDataReader rdr;

                rdr = cmd2.ExecuteReader();
                while (rdr.Read())
                {

                    string user = rdr.GetString("Username");
                    comboBox_Employee.Items.Add(user);
                }
            }
}

how to add checkbox for every record and code behind to display related records in datagrid view?