Since multiple inheritance is bad (it makes the source more complicated) C# does not provide such a pattern directly. But sometimes it would be helpful to have this ability. C# and the .net CLR have not implemented MI because they have not concluded how it would inter-operate between C#, VB.net and the other languages yet, … Read more
It’s the null conditional operator. It basically means: “Evaluate the first operand; if that’s null, stop, with a result of null. Otherwise, evaluate the second operand (as a member access of the first operand).” In your example, the point is that if a is null, then a?.PropertyOfA will evaluate to null rather than throwing an exception – it will then compare that null reference with foo (using string’s == overload), … Read more
Take a look at System.IO.File.Move, “move” the file to a new name.
This is because Point is a value type (struct). Because of this, when you access the Origin property you’re accessing a copy of the value held by the class, not the value itself as you would with a reference type (class), so if you set the X property on it then you’re setting the property on the copy and then discarding it, leaving … Read more
Use a lambda expression Note: C# has a built-in syntax for properties. Instead of writing getter and setter as ordinary methods (as you might be used to from Java), write value is a contextual keyword known only in the set accessor. It represents the value assigned to the property. Since this pattern is often used, C# … Read more
For what it’s worth, a Dictionary is (conceptually) a hash table. If you meant “why do we use the Dictionary<TKey, TValue> class instead of the Hashtable class?”, then it’s an easy answer: Dictionary<TKey, TValue> is a generic type, Hashtable is not. That means you get type safety with Dictionary<TKey, TValue>, because you can’t insert any random object into it, and you don’t have to cast the … Read more
Please use the attributes from the System.Web.Http namespace on your WebAPI actions: The reason why it doesn’t work is because you were using the attributes that are from the MVC namespace System.Web.Mvc. The classes in the System.Web.Http namespace are for WebAPI.
As suggested here this is what you should do: You may get this error when trying to browse an asp.net application. The debug information shows that “This error can be caused by a virtual directory not being configured as an application in IIS.” However, this error occurs primarily out of 2 scenarios. When you create an new … Read more
this will never work. OnTriggerEnter needs a Collider not an Collision. Try this:
How to perform left outer join in C# LINQ to objects without using join-on-equals-into clauses? Is there any way to do that with where clause? Correct problem: For inner join is easy and I have a solution like this but for left outer join I need a solution. Mine is something like this but it’s not working where JoinPair is a … Read more