我正在尝试创建一个库，用于在WPF中从可观察的集合中创建报表，但是我不知道如何循环ObservableCollection并将值写入FlowDocument表中。我尝试将通用集合转换为IEnumerable，但我不断获得

抛出异常：“ System.NullReferenceException”

目标是编写一个可以接受所有ObservableCollection类型的库，因此我已经编写了此类（代码段）：

public class Report_Definition<T> : INotifyPropertyChanged
{
        public Report_Definition(FlowDocument doc,ObservableCollection<T> data)
        {
            Fill_data(data,doc);
        }

        private void Fill_data(ObservableCollection<T> data,FlowDocument doc)
        {
            //I only take 25 records from ObservableCollection - to create more Tables
            for (int i = 0; i < data.Count; i += 25)
            {
                var list = (from c in data select c).Skip(i).Take(25);

                 if (i < 25) //Test for only first Table
                {
                    for (int row = 0; row < list.Count(); row++)
                    {
                        TableRow my_cell = new TableRow();

                        foreach (var item in list)
                        {
                            foreach (var w in item as IEnumerable<T>) //ERROR HERE !!!
                            {
                                my_cell.Cells.Add(new TableCell(new Paragraph(new Run(w.ToString()))) { Padding = new Thickness(2),BorderBrush = brushes.Black,BorderThickness = new Thickness(0.7) });
                            }

                        }

                        TableRowGroup whole_row = new TableRowGroup();
                        whole_row.Rows.Add(my_cell);
                        My_table.RowGroups.Add(whole_row); //I get reference of this elsewhere...
                    }
                }
        }
}

这是我的Employee课：

public class Employee : INotifyPropertyChanged
{
        public string Name { get; set; }
        public string Surname { get; set; }
        public string Address { get; set; }
        public string Country { get; set; }

        #region INotifyPropertyChanged

        public event PropertyChangedEventHandler PropertyChanged;
        private void OnPropertyChanged(string propertyName)
        {
            PropertyChanged?.Invoke(this,new PropertyChangedEventArgs(propertyName));
        }

        #endregion
}

因此，大写字母我使用ObservableCollection(Employee)，并且我想遍历此集合中的每个Employee以在表行中写入值。

当前，此代码仅将类型写入单元格，例如My_Project.Model.Employee。

有人可以告诉我如何正确执行此操作吗？

P.S .：如您所见，我正在采用MVVM方法。