How to sort my datagrid table

I fill datagrid from DataBase using sqlite - ShowDataBase(string a);

Then I want to sort It,When Button is Clicked (Note! I want to sort it only in program(not modding the DB). Just want to delete wrong rows)

        private void Button_Click(object sender, RoutedEventArgs e)
    {
        ShowDataBase("Pacients");

        if ((bool)SortFromCheckBox.IsChecked)
        {
            //Delete all data earlier than data that user asked for
            for (int i = DataGridMain.Items.Count - 1; i >= 0; i--)
            {
                DataGridRow row = (DataGridRow)DataGridMain.ItemContainerGenerator.ContainerFromIndex(i);
                var item = DataGridMain.Items[i];
                var data = DataGridMain.Columns[4].GetCellContent(item);
                if ((Convert.ToDateTime(data)) <= (Convert.ToDateTime(SortFromTextBox.Text)))
                {
                    //Smth to delete row № i from datagrid

                }
            }
        }
        if ((bool)SortUntilCheckBox.IsChecked)
        {
            //Delete all data older than data that user asked for
        }
        if ((bool)SortByClientCheckBox.IsChecked)
        {
            //Delete all data where client cell is != name that user want to sort by
        }
        if ((bool)SortByDoctorCheckBox.IsChecked)
        {
            //Delete all data where doctor cell is != name that user want to sort by
        }
    }