LINQ - ASP.NET (MCQ) questions and answers

ANSWER: Methods, properties, events, indexers

Explanation:
An interface can contain declaration of methods, properties, events, indexers but you cannot provide the definition.

ANSWER: CommitChanges is a method of DataContext.

Explanation:
In LINQ, CommitChanges is a method of DataContext class. DataContext class is used to connect with database, retrieve objects from it, and submit changes back to it.
Example:
DataContext context = new DataContext( “ Provide your connection string ” );
You can also create and delete database as given below.
Create database
context.CreateDatabase();

Delete database
context.DeleteDatabase();

ANSWER: All of the above

Explanation:
In the above question all options are correct. By default LINQ uses deferred query execution. It means that LINQ queries are always executed when you iterated the query variable, not when the query variable is created. LINQ queries actually run when they are iterated over in a foreach loop.

ANSWER: All of the above

Explanation:
In the above question all the options are correct. Any .NET Framework collection that implements IEnumerable(T) or that inherit from IEnumerable(T) can be queried using LINQ.

ANSWER: Anonymous types are class types that derive directly from object.

Explanation:
Anonymous types are class types that derive directly from object. You cannot cast to other type except object.Anonymous types are created by using new operator along with an object initializer.

Example:
var v = new {Website = “ CareerRide ”, Message = " Welcome " };
Console.WriteLine(v. Website + v.Message);

ANSWER: Dynamic type is static type.

Explanation:
If you declare anything as dynamic then its type is checked at runtime. Dynamic type is static type.

ANSWER: Variables introduced within a lambda expression are not visible in the outer method.

Explanation:
A lambda expression is an anonymous function that you can use to create delegates
A variable, declared inside the anonymous method can’t be accessed outside the anonymous method but a variable, declared outside the anonymous method can be accessed inside the anonymous method.

ANSWER: Each input parameter in the lambda must be implicitly convertible to its corresponding delegate parameter.

Explanation:
Each input parameter in the lambda must be implicitly convertible to its corresponding delegate parameter because A delegate can refer only those methods that have same signature as delegate.

ANSWER: The lambda must contain the same number of parameters as the delegate type.

Explanation:
The lambda must contain the same number of parameters as the delegate type.
A delegate can refer only those methods that have same signature as delegate and lambda is nothing but anonymous function that can be used to create delegates.

ANSWER: 1, 2

Explanation:
A lambda expression is an anonymous function that can be used to create delegates. There are two types of lambda expression, Expression Lambda and Statement Lambdas.

Example:
delegateint del(int i);
static void Main(string[ ] args)
{
delmyDelegate = x => x * x * x;
int j = myDelegate(4);
}
In the above given example x is the parameter that is acted on by the expression x * x * x. So the value of x will be cube of x.