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Closed 11 years ago.
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What are Extension Methods?
Extension Methods
Could someone explain the concept of extensions methods with examples if possible please
Extension methods enable you to "add" methods to existing types without creating a new derived type, recompiling, or otherwise modifying the original type
Refer to:
Extension Methods (C# Programming Guide)
Related
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How do I use reflection to call a generic method?
(8 answers)
Closed 2 years ago.
Why can't I do this?
services.AddSingleton<Type.GetType("ShoppingCartCache",true)>();
OR is there a better way of passing from a string
The method also has an overload to pass a type as parameter. So you can do:
services.AddSingleton(typeof(ShoppingCartCache));
Same also works with your example (although more prone to runtime errors):
services.AddSingleton(Type.GetType("ShoppingCartCache",true));
The reason it doesn't work is because generic types must be static, thus known at compilation.
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What are attributes in .NET?
(11 answers)
Closed 6 years ago.
Sometimes I see them with methods, classes etc.
What does it do?
When should i use them?
Example:
[Obsolete]
public static void MyMethod()
{
//some code
}
An attribute is a declarative tag that is used to convey information to runtime about the behaviors of various elements like classes, methods, structures, enumerators, assemblies etc. in your program. You can add declarative information to a program by using an attribute
https://msdn.microsoft.com/en-us/library/aa288454(v=vs.71).aspx
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C# adding implict conversions to existing types
(2 answers)
Closed 9 years ago.
I have two custom classes for which I want to implement casts between each other. I only have the DLLs of the two projects and not the code. Can I use extension methods to implement the cast or would I need to do something else?
I'd suggest that you implement your own mappers between the 2 classes or use mapping tools such as AutoMapper or ValueInjecter
You will have to use either extension methods or some other mapping. You could also use http://automapper.codeplex.com/
I don't think there is a way to do it. Anyway, do you really need the code to look like cast? Sometimes when you implement operators or casts for custom types the code may become harder to understand. I would suggest to create separate utility to convert types which would be more obvious for someone who sees the code for the first time.
This question already has answers here:
Closed 12 years ago.
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CompilerServices.Operators equivalent on C#
I was looking for Microsoft.CSharp.CompilerServices.Operators but couldn't find it.
No there is no real equivalent to this in the C# runtime assembly.
However many these methods are essentially implementing the late bound operations for VB.Net in a declarative method (and indeed there are cases where the late binder simply just defers to these methods for operations). So these could be replicated in C# by defining methods which just explicitly defer to the C# dynamic binder.
For example, the rough equivalent of DivideObject in C# would be the following
public static dynamic DivideObject(dynamic left, dynamic right)
{
return left / right;
}
This question already has answers here:
Closed 12 years ago.
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Try to describe polymorphism as easy as you can
What is polymorphism?
Please read MSDN which covers it in reference to c#,
Basically a derived class inherits from another class it gets all its methods,events and properties, and every type is polymorphic in .NET since they all have Object as their base class.