The ?? operator is also known as the null-coalescing operator. It returns the left side operand if the operand is not null else it returns the right side operand. This article explains what is nullable types, the null coalescing operator, and unique ways to use the null-coalescing operator in C#.

Contents

• C# Nullables
  • Shorthand Syntax For Nullable Types
• What Is Null Coalescing Operator In C#?
• Null Coalescing Operators In Practical Scenarios
• Further Reading
• References

C# Nullables

A reference type can have an actual value of null, meaning it has no value. A value type can’t have a value of null.

For example, how would you express that some boolean value is true, false, or unknown? Regular Boolean can be only true or false.

Contents

• What Are Events In C#?
• Understanding Delegates In C#
  • Using A Delegate In C#
  • Multicast Delegates In C#
  • Covariance and Contravariance In C#
    • Covariance With Delegates
    • Contravariance With Delegates
• Lambda Expressions In C#
• Events In C#
• Further Reading
• References

What Are Events In C#?

An event can be used to provide notifications. You can subscribe to an event if you are interested in those notifications. You can also create your own events and raise them to provide notifications when something interesting happens. The .NET Framework offers built-in types that you can use to create events. By using delegates, lambda expressions, and anonymous methods, you can create and use events in a comfortable way.

Contents

• What are Services in Angularjs?
• Why use Services in Angularjs?
• Angularjs Service Example
• Different Methods To Create AngularJS Services
  • Angularjs Provider Example
  • Factory Method In AngularJs
  • Service Method In AngularJs
    • Difference Between Service And Factory In Angularjs
  • Angularjs Value Service
  • Angularjs Constant Service
• Conclusion
• References

What are Services in Angularjs?

Angularjs Services are functions or objects that contains reusable code that can get consumed accross app by controllers, directives, filters and other services using Dependency Injection Mechanism of Angularjs.

From getting client request to sending a response, the Asp.NET MVC lifecycle is bit complex. This lifecycle is totally different from old Asp.NET Webforms. As the page in Webforms has page lifecycle many people compare this with Asp.NET MVC lifecycle which is totally a different thing.