Brief Summary
Bill Wagner discusses underutilized C# features that can improve code readability and productivity. He emphasizes the importance of adopting these features gradually to avoid disrupting ongoing projects. The presentation covers pattern matching, file-scoped namespaces, init and required properties, string literals, records, and collection expressions, providing practical examples and usage scenarios for each.
- Pattern matching simplifies complex conditional logic.
- File-scoped namespaces reduce code nesting.
initandrequiredproperties enhance data encapsulation.- String literals and interpolated strings improve string manipulation.
- Records streamline data-centric type definitions.
- Collection expressions simplify collection initialization.
Pattern Matching
Pattern matching offers a declarative approach to replace complex if-else and switch statements. It enhances code readability by clearly mapping inputs to outputs. The compiler provides warnings for incomplete or unreachable patterns, ensuring logical correctness. Using pattern matching can simplify code with multiple nested if statements by making the logic more transparent. A common mistake involves using and, not, and or without proper parentheses, which can lead to unexpected behavior due to operator precedence. The compiler will soon issue warnings for such cases to improve code correctness.
File-Scoped Namespaces
File-scoped namespaces reduce code nesting by eliminating an entire level of indentation. This feature simplifies the structure of files, making code more readable and providing more horizontal space for logic. While it introduces whitespace diffs, these can be managed by disabling whitespace diffs during code reviews to focus on the actual changes. It is recommended to apply this feature incrementally during routine code modifications rather than performing a sweeping change across the entire codebase.
Init and Required Properties
The init and required keywords enhance property behavior, aligning them more closely with design intentions. The required keyword ensures that a property is set during object initialization, with the compiler issuing a warning if it is not. The init keyword creates a read-only property that can only be set during object initialization using an object initializer, preventing subsequent modifications. This combination allows for clear intent expression regarding data immutability and initialization constraints.
String Literals
C# offers several ways to handle strings, including basic strings with escape characters, verbatim strings (using @ to reduce escape sequences), and raw string literals (using triple quotes """). Raw string literals are particularly useful for JSON and other formats with many quotes, improving readability. Interpolated strings (using $) allow embedding expressions directly within strings. Recent enhancements support newlines and spacing within interpolated expressions. Multiple dollar signs can be used to handle nested curly braces in formats like JSON, providing flexibility and clarity in string construction.
Records
Records, defined using the record keyword, are designed to hold data and automatically generate methods for value-based equality (Equals, GetHashCode, etc.). Records can be either classes or structs. The with keyword enables non-destructive mutation, creating a copy of a record with specified properties modified. Using the record declaration on a struct type improves equality implementation by allowing the compiler to generate optimized code based on known fields.
Collection Expressions
Collection expressions simplify collection initialization using bracket syntax. The compiler can optimize memory usage by allocating collections on the stack when appropriate, such as when passing them as arguments to methods. This feature eliminates the need for explicit new declarations and stack allocation, improving code conciseness and efficiency.
