Box or unbox to convert between value types
Cast types
Convert types
Handle dynamic types
Ensure interoperability with unmanaged code, for example, dynamic keyword

Enforce encapsulation by using properties, by using accessors (public, private, protected), and by using explicit interface implementation

Design and implement an interface
Inherit from a base class
Create and implement classes based on the IComparable, IEnumerable, IDisposable, and IUnknown interfaces

Create and apply attributes
Read attributes
Generate code at runtime by using CodeDom and lambda expressions
Use types from the System.Reflection namespace (Assembly, PropertyInfo, MethodInfo, Type)

Manipulate strings by using the StringBuilder, StringWriter, and StringReader classes
Search strings
Enumerate string methods
Format strings

Validate JSON data
Data collection types
Manage data integrity
Evaluate a regular expression to validate the input format
Use built-in functions to validate data type and content out of scope: writing regular expressions

What are Errors
Catching Errors and Exceptions
Raising Exceptions
Creating Your Own Exceptions
Throwing and Catching Exceptions

Choose an appropriate encryption algorithm
Manage and create certificates
Implement key management
Implement the System.Security namespace
Hashing data Encrypt streams

Create and manage compiler directives
Choose an appropriate build type
Manage programming database files and symbols

Implement logging and tracing
Profiling applications
Create and monitor performance counters
Write to the event log

Read and write files and streams
Read and write from the network by using classes in the System.Net namespace
Implement asynchronous I/O operations

Retrieve data from a database
Update data in a database
Consume JSON and XML data
Retrieve data by using web services

Serialize and deserialize data by using binary serialization, custom serialization, XML Serializer, JSON Serializer, and Data Contract Serializer

Store and retrieve data by using dictionaries, arrays, lists, sets, and queues
Choose a collection type
Initialize a collection
Add and remove items from a collection
Use typed vs. non-typed collections
Implement custom collections
Implement collection interfaces