Silverlight 4 RIA service issue - silverlight

Question

Hi I have created a sample database application in Silverlight by following a tutorial. I am trying to insert a record in DB but it throws an error Submit operation failed validation. Please inspect Entity.ValidationErrors for each entity in EntitiesInError for more information. I am using Entity framework for DAL. My code is given below. Exception occure when I insert a record. But Iam not sure at which stage exception occurs.
RecordInsertPage.cs file
public partial class BookRegistaeration : ChildWindow
{
public Book newBook { get; set; }
public BookRegistaeration()
{
InitializeComponent();
newBook = new Book();
AddBookForm.CurrentItem =AddBookForm;
AddBookForm.BeginEdit();
}
private void OKButton_Click(object sender, RoutedEventArgs e)
{
AddBookForm.CommitEdit();
this.DialogResult = true;
}
private void CancelButton_Click(object sender, RoutedEventArgs e)
{
newBook = null;
AddBookForm.CancelEdit();
this.DialogResult = false;
}
}
Service.cs Page
public class OrganizationService : LinqToEntitiesDomainService<LibraryEntities1>
{
public IQueryable<Book> GetBooks()
{
return this.ObjectContext.Books.OrderBy(e => e.BookId);
}
public void InsertBook(Book book)
{
//book.Title = "Hello book";
//book.Author = "Ali";
//book.Category = "Humanity";
if ((book.EntityState != EntityState.Detached))
{
this.ObjectContext.ObjectStateManager.ChangeObjectState(book, EntityState.Added);
}
else
{
this.ObjectContext.Books.AddObject(book);
}
}
public void UpdateBook(Book currentBook)
{
this.ObjectContext.Books.AttachAsModified(currentBook, this.ChangeSet.GetOriginal(currentBook));
}
public void DeleteBook(Book book)
{
if ((book.EntityState != EntityState.Detached))
{
this.ObjectContext.ObjectStateManager.ChangeObjectState(book, EntityState.Deleted);
}
else
{
this.ObjectContext.Books.Attach(book);
this.ObjectContext.Books.DeleteObject(book);
}
}
}
private void LibraryDataSource_SubmittedChanges(object sender, SubmittedChangesEventArgs e)
{
if (e.HasError)
{
MessageBox.Show(string.Format("Changes were not saved: {0}", e.Error.Message));
e.MarkErrorAsHandled();
}
submitButton.IsEnabled = true;
}
void addBook_Closed(object sender, EventArgs e)
{
BookRegistaeration book = (BookRegistaeration)sender;
if (book.newBook != null)
{
OrganizationContext _OrganizationContext = (OrganizationContext)(LibraryDataSource.DomainContext);
_OrganizationContext.Books.Add(book.newBook);
LibraryDataSource.SubmitChanges();
}
}

Answer 1

Try doing as the exception message suggests, put a breakpoint on your SubmittedChanges event to inspect that exception object for which you should be able to see Entity.ValidationErrors for each entity in EntitiesInError.
This should tell you which of the fields in the object you are trying to add has failed the validation check, you may have null data in fields which cannot be null. You may find string properties are not allowed to be empty.
Try also to ensure your form is properly populating the object you will be adding, you could place a breakpoint before CommitEdit is called and inspect the object state.

Answer 2

i do not understand this line !
AddBookForm.CurrentItem =AddBookForm;
why did you write this?
it should be something like this
AddBookForm.CurrentItem = your class object !