datacontext

Normally when you want a databound control to 'update,' you use the "PropertyChanged" event to signal to the interface that the data has changed behind the scenes. For instance, you could have a textblock that is bound to the datacontext with a property "DisplayText" <TextBlock Text="{Binding Path=DisplayText}"/> From here, if the DataContext raises the PropertyChanged event with PropertyName "DisplayText," then this textblock's text should update (assuming you didn't change the Mode of the binding). However, I have a more complicated binding that uses many properties off of the datacontext to

Is it possible to access the DataContext object behind an IQueryable? If so, how? DataContext is specific to LINQ to SQL, so presumably you're talking about LINQ to SQL queries? If so, there's no safe way to do this - you have to resort to a hack such as using reflection to retrieve the private "context" field of the underlying DataQuery object: static DataContext GetContext (IQueryable q) { if (!q.GetType().FullName.StartsWith ("System.Data.Linq.DataQuery`1")) return null; var field = q.GetType().GetField ("context", BindingFlags.NonPublic | BindingFlags.Instance); if (field == null) return

I have an object in my view model that has a bunch of properties, some of them will occasionally be null. I don't want to just show some controls if these particular controls are null. How would I go about hiding the control if the bind is null? I was thinking of some sort of converter, but don't know how I'd go about doing it exactly. Any ideas? edit: sorry, I should mention that this will also be in Silverlight, so I'm not sure if Style triggers would work...? Prince Ashitaka Have a converter like follows, public sealed class NullToVisibilityConverter : IValueConverter { public object

I have a DataContext (Linq to Sql) with over 100 tables, is it possible to get a list of all those tables and lets say print them to the console? This might be a silly question. Thanks. It's much easier than above and no reflection required. Linq to SQL has a Mapping property that you can use to get an enumeration of all the tables. context.Mapping.GetTables(); You can do this via reflection. Essentially, you iterate over the properties in your DataContext class. For each property, check to see if that property's generic parameter type has the TableAttribute attribute. If so, that property

I've been doing some searching on the internet, but I can't seem to find the awnser. What exceptions can a DataContext throw? Or to be more specific, what exceptions does the DataContext.SubmitChanges() method throw? EDIT For reference, here a List of possible known exceptions that could be thrown by the L2S DataContext: SqlException ChangeConflictException DuplicateKeyException ForeignKeyReferenceAlreadyHasValueException OutOfMemoryException (when not correctly disposing the DataContext) You're right, MSDN is not a great help here. This is what I can remember from the top of my head:

I want to be able to create an instance of the DataContext object for my WPF StartupUri window in XAML, as opposed to creating it code and then setting the DataContext property programmaticly. The main reason is I don't need to access the object created externally and I don't want to have to write code behind just for setting the DataContext . I'm sure I've read somewhere how to instantiate the DataContext object in XAML but I can't find it in any of the usual places... You add an XML namespace for whatever namespace your DataContext lives in, create an instance of it in the Window Resources

Can I update my employee record as given in the function below or do I have to make a query of the employee collection first and then update the data? public int updateEmployee(App3_EMPLOYEE employee) { DBContextDataContext db = new DBContextDataContext(); db.App3_EMPLOYEEs.Attach(employee); db.SubmitChanges(); return employee.PKEY; } Or do I have to do the following? public int updateEmployee(App3_EMPLOYEE employee) { DBContextDataContext db = new DBContextDataContext(); App3_EMPLOYEE emp = db.App3_EMPLOYEEs.Single(e => e.PKEY == employee.PKEY); db.App3_EMPLOYEEs.Attach(employee,emp); db

Suppose I have IRepository interface and its implementation SqlRepository that takes as an argument LINQ to SQL DataContext. Suppose as well that I have IService interface and its implementation Services that takes three IRepository, IRepository and IRepository. Demo code is below: public interface IRepository<T> { } public class SqlRepository<T> : IRepository<T> { public SqlRepository(DataContext dc) { ... } } public interface IService<T> { } public class Service<T,T1,T2,T3> : IService<T> { public Service(IRepository<T1> r1, IRepository<T2>, IRepository<T3>) { ... } } Is it any way while