Yes, generics is a good choice. The key to achieving type-safety (and being identify the type with the Type property is to add an abstraction between the list and Field<T> class. Have Field<T> implement the interface IField. This interface doesn’t need any members. Then declare your list as being List<IField>. That way you constrain the … Read more
You need to convert the code to an expression tree. using System; using System.Linq; using System.Linq.Expressions; using System.Reflection; namespace WindowsFormsApplication1 { static class Program { [STAThread] static void Main() { using (var context = new NorthwindEntities()) { IQueryable<Customer> query = context.Customers; query = Simplified<Customer>(query, “CustomerID”, “ALFKI”); var list = query.ToList(); } } static IQueryable<T> Simplified<T>(IQueryable<T> … Read more
what does it mean “generic type parameters that are filled in with concrete type parameters when the trait is used” An example that won’t work is when the type parameter is part of a method: trait Foo { fn foo<T>(t: T) {} } When a function has a type parameter, Rust will monomorphize the function … Read more
IF the model which you are passing to DAL through your BL is a view-model then the logic will be in your DAL otherwise you should not pass a model which will perform 3 insert for 3 different tables.
Tim Larson already offered a great solution for this boilerplate code in his blog: public static class DbSetMocking { private static Mock<DbSet<T>> CreateMockSet<T>(IQueryable<T> data) where T : class { var queryableData = data.AsQueryable(); var mockSet = new Mock<DbSet<T>>(); mockSet.As<IQueryable<T>>().Setup(m => m.Provider) .Returns(queryableData.Provider); mockSet.As<IQueryable<T>>().Setup(m => m.Expression) .Returns(queryableData.Expression); mockSet.As<IQueryable<T>>().Setup(m => m.ElementType) .Returns(queryableData.ElementType); mockSet.As<IQueryable<T>>().Setup(m => m.GetEnumerator()) .Returns(queryableData.GetEnumerator()); return … Read more
There are two distinct flavors of generics in TypeScript: generic functions and generic types. A generic function declares its generic type parameter (or parameters) on the call signature of the function: type IdentityGenFunc = <T>(t: T) => T The type parameter on a generic function (T above) isn’t specified until the function is actually called, … Read more
Unfortunately, generic Swift classes are not visible to Objective-C code and also are not supported in Interface Builder (in storyboards and xibs). I find these two points closely related. As a solution I would suggest you to use aggregation: do not make you view controller generic, but extract some logic to another (generic) class and … Read more
This is essentially just like the type-safe heterogeneous container described by Joshua Bloch, except you can’t use the Class to cast the result. Weirdly, I can’t find a great example existing on SO, so here is one: package mcve; import java.util.*; import java.util.function.*; class ClassToConsumerMap { private final Map<Class<?>, Consumer<?>> map = new HashMap<>(); @SuppressWarnings(“unchecked”) … Read more
Read the Java Generics Tutorial. The thing between the angle brackets is a type parameter – Comparable is a generic class, and in this case the angle brackets mean that the class is comparable to other BigIntegers. For a little more clarification in this case, have a look at the Javadocs for Comparable in 1.5. … Read more
T is inferred to be Object, and both arguments are getting implicitly upcast. Thus the code is equivalent to: Main.<Object>random((Object)”string1″, (Object)new Integer(10)); What may be even more surprising is that the following compiles: random(“string1”, 10); The second argument is getting auto-boxed into an Integer, and then both arguments are getting upcast to Object.