WPF的datagrid获取单元格怎么实现MVVM模式...

问题1：无法解决界面刷新问题，值总会被一遍一遍的被初始化覆盖
仿佛又回到了最初的起点，那就是datagrid在多线程下无法刷新的问题
例：

                    View                        
                    <TextBox .... Text = {Binding Offset,  Mode = TwoWay, UpdateSourceTrigger = PropertyChanged}>
                    <DataGrid ... BeginningEdit = "Edit_bg">
                    主XML下的Cs:
                    DataContx = new View();
                    private void Edit_bg (object sender, DataGridCellEditEndingEventArgs e)
                    {
                            View.BG(( e.Column.GetCellContent(e, row) as TextBlock).Text);
                    }

                    ViewModel:
                    private string offset;
                    public string Offset
                    {
                            get{return offset;}
                            set{
                                        offset =value;
                                        RaisePropertyChange(nameof(Offset));
                            }
                    }

                    public View()
                    {
                            offset = "0";
                    }

                    BG(string value)
                    {
                            offset = value;
                            Offset = offset;
                    }

View.BeginningEdit里面保存的代码的逻辑怎么写的