wpf mvvm与实体框架的两种方式数据绑定

Question

I have classes generated by Entity Framework as follows. My requirement is to load data from the database into a List View and if any checked changes happen in the List View, store it back.

For that purpose in my model, I have written another partial class as below that implements INotifyPropertyChanged . I want to use my Entity Framework classes as models.

Along the same lines I have a view containing a List View for displaying Name and Location and a check box for each row to display checked state. So for the checkbox, an example of the logic I have written is CheckBox IsChecked=true , mode=two way , UpdateSourceTrigger=PropertyChanged . I use a OnCheckedChanged event to call db.SaveChanges in my view model.

db is object of type SampleDbContext . But it seems the binding is not happening, ie checked changes are not stored into the database.

Why are checked changes not saving to the database?

Entity Framework classes:

public partial class Datagrid
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Location { get; set; }
    public Nullable<bool> IsChecked { get; set; }
}

public partial class SampleDbContext : DbContext
{
    public SampleDbContext() : base("name=SampleDbContext")
    {}

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        throw new UnintentionalCodeFirstException();
    }

    public virtual DbSet<Datagrid> Datagrids { get; set; }
}

My Custom Class in the Models: (This is a sample code may have some spelling mistakes but please ignore it)

[MetaDataType(typeof(grid))]
public partial class DataGrid
{}

public class grid:INotifyPropertyChanged
{
    public Nullable<bool> IsChecked 
    {   
        get { return IsChecked; }
        set
        {
            IsChecked=value;
            OnPropertyChanged("IsChecked");
        }
    }   

    //INotifyPropertyChanged Implementation....
}

Answer 1

You are calling the same Property within your property setter. IsChecked=value. Create a private field to store the isChecked value.

[MetaDataType(typeof(grid))]
public partial class DataGrid
{
}

public class grid:INotifyPropertyChanged
{
    private bool? m_IsChecked;
    public Nullable<bool> IsChecked  
    get
    {
        return m_IsChecked;
    }
    set
    {
        if(m_IsChecked != value)
        {
            m_IsChecked=value;
            OnPropertyChanged("IsChecked");
        }
    }
}