Anonymous Types

• Private nested type with read-only properties is created.
• Var keyword is needed to reference an anonymous type, because the type’s name is compiler-generated.

Basic

• General purpose.
• Object oriented.
• Type safe.
• Case sensitive.

Attributes

• Attributes are an extensible mechanism for adding custom information to code elements.
• Named attribute are parameters for attribute type’s constructor.
• Positional attributes are public fields or properties.
• [AttributeUsage (AttributeTargets.Method)] 

Miscellaneous

• foreach statement is a consumer of an enumerator, an iterator is a producer of an enumerator.
• yield and yield break.
• int? i = null; //? Allows null
• Extension methods allow an existing type to be extended with new methods.
• Instance method has precedence over extension method.

Lamda Expression

• (parameters) => expression-or-statement-block.
• Local variables and parameters referenced by a lambda expression are called outer variables or captured variables.
• A lambda expression that includes outer variables is called a closure.

Event

• Event formalizes the broadcaster, subscriber pattern.
• Code within the broadcaster type has full access to delegate.

Code outside of broadcaster can only perform += and -= operations. No delegate invocation.