在WPF中接收到空参数的Observable Collection绑定DataGrid时出现问题

Question

我是在WPF中使用C＃进行的新编程，但出现错误：

我已经将WPF DataGRid与一个Observable集合绑定，该集合从数据库接收参数。 首先，当Observable Collection从存储过程中接收所有参数时，APP函数通常正常运行，但是当我在数据源中存储了null参数（StoredProcedure）时，Observable Collection接收到null参数，则应用程序崩溃，并且它没有开始...。页面只是保持空白

如何解决这个问题？

首先在这里，我向页面展示用作Dada上下文的类

class ColeccionDeDatos : INotifyPropertyChanged
{
    private RegistroBLL regBll = new RegistroBLL();
    private DivisionBLL divBll = new DivisionBLL();
    private BrigadaBLL briBll = new BrigadaBLL();
    private BatallonBLL batBll = new BatallonBLL();
    private TropasBLL tropBll = new TropasBLL();
    private CompañiaBLL compBLL = new CompañiaBLL();
    private EstudioBLL estBll = new EstudioBLL();
    private RegistroFullBLL regFullBll = new RegistroFullBLL();


    private ObservableCollection<RegistroFullBO> coleccionFullRegistro = new ObservableCollection<RegistroFullBO>();
    public ObservableCollection<RegistroFullBO> ColeccionFullRegistro
    {
        get { return coleccionFullRegistro; }
        set { coleccionFullRegistro = value; }

    }

    private ObservableCollection<RegistroBO> coleccionRegistro = new ObservableCollection<RegistroBO>();
    public ObservableCollection<RegistroBO> ColeccionRegistro
    {
        get { return coleccionRegistro; }
        set { coleccionRegistro = value; }

    }

    private ObservableCollection<DivisionBO> coleccionDivision = new ObservableCollection<DivisionBO>();
    public ObservableCollection<DivisionBO> ColeccionDivision
    {
        get { return coleccionDivision; }
        set { coleccionDivision = value; }

    }

    private ObservableCollection<BrigadaBO> coleccionBrigada = new ObservableCollection<BrigadaBO>();
    public ObservableCollection<BrigadaBO> ColeccionBrigada
    {
        get { return coleccionBrigada; }
        set { coleccionBrigada = value; }
    }

    private ObservableCollection<BatallonBO> coleccionBatallon = new ObservableCollection<BatallonBO>();
    public ObservableCollection<BatallonBO> ColeccionBatallon
    {
        get { return coleccionBatallon; }
        set { coleccionBatallon = value; }
    }

    private ObservableCollection<TropasBO> coleccionTropas = new ObservableCollection<TropasBO>();
    public ObservableCollection<TropasBO> ColeccionTropas
    {
        get { return coleccionTropas; }
        set { coleccionTropas = value; }
    }

    private ObservableCollection<CompañiaBO> coleccionCompañia = new ObservableCollection<CompañiaBO>();
    public ObservableCollection<CompañiaBO> ColeccionCompañia
    {
        get { return coleccionCompañia; }
        set { coleccionCompañia = value; }
    }

    private ObservableCollection<EstudioBO> coleccionEstudio = new ObservableCollection<EstudioBO>();
    public ObservableCollection<EstudioBO> ColeccionEstudio
    {
        get { return coleccionEstudio; }
        set { coleccionEstudio = value; }
    }

    public ColeccionDeDatos() 
    {
        ColeccionRegistro = regBll.ObtenerFilasRegistro();
        ColeccionDivision = divBll.ObtenerFilasDivision();
        ColeccionBrigada = briBll.ObtenerFilasBrigada();
        ColeccionBatallon = batBll.ObtenerFilasBatallon();
        ColeccionTropas = tropBll.ObtenerFilasTropas();
        ColeccionCompañia = compBLL.ObtenerFilasCompañia();
        ColeccionEstudio = estBll.ObtenerFilasEstudio();
        ColeccionFullRegistro = regFullBll.ObtenerFilasRegistro();
    }

然后在页面后面的代码中，将此类的实例分配为Page元素的DataContext。

private void Page_Loaded(object sender, RoutedEventArgs e)
    {
        try
        {
            PagRegistroName.DataContext = colData;

        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message + "+++++++++++");
        }

    }

对于我的数据网格来说：

<DataGrid Name="dgRegistro" Margin="5" SelectionChanged="dgRegistro_SelectionChanged"
                            ItemsSource="{Binding Path=ColeccionFullRegistro}" AutoGenerateColumns="False">

在每个单元格模板中，我使用了一个组合框：

<DataGridTemplateColumn.CellEditingTemplate >
                        <DataTemplate>
                            <ComboBox x:Name="cmbDivision" Text="{Binding Path=Division, Mode=TwoWay}"     
                                      ItemsSource="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=Page, AncestorLevel=1},
                                      Path=DataContext.ColeccionDivision}"  DisplayMemberPath="Nom_division" SelectionChanged="cmbDivision_SelectionChanged" SelectedValuePath="Nom_division">
                            </ComboBox>
                        </DataTemplate>
                    </DataGridTemplateColumn.CellEditingTemplate>

所以它是我想要的功能

https://onedrive.live.com/redir?resid=B371651233630F9A!153&authkey=!ADzRW6OvvdMZiMI&v=3&ithint=photo%2c.png

对应于数据库中的表

但是，当我直接在数据库中输入NULL值时

http://1drv.ms/RrN5qO

该应用程序已启动，但每次仍为空白，因此出了点问题。

知道是什么问题吗？

Answer 1

像这样过滤：

if(MyProperty == null)
{ 
    MyProperty = string.Empty;
]