StringExtensions

Provides comprehensive string manipulation, validation, transformation, and utility methods.

Overview

The StringExtensions class offers 40+ extension methods for string operations including validation, case conversion, encoding, manipulation, analysis, and generation. All methods are designed to be null-safe and performance-optimized.

API Reference

StringExtensions

Core Methods

Basic Utilities

NullIfEmptyOrWhiteSpace(string? input)

Returns null if the string is null, empty, or contains only whitespace.

string? result = "   ".NullIfEmptyOrWhiteSpace(); // null
string? result = "hello".NullIfEmptyOrWhiteSpace(); // "hello"

RemoveSpecialCharacters(string? input)

Removes special characters, keeping only letters, digits, whitespace, and hyphens.

string clean = "he!!o-w@rld".RemoveSpecialCharacters(); // "heo-wrld"

String Validation

Email and URL Validation

IsValidEmail(string? input)

Validates email address format using MailAddress parsing.

bool valid = "test@example.com".IsValidEmail(); // true
bool invalid = "invalid-email".IsValidEmail(); // false

IsValidUrl(string? input)

Validates URL format using Uri.IsWellFormedUriString.

bool valid = "https://example.com".IsValidUrl(); // true
bool invalid = "not-a-url".IsValidUrl(); // false

Numeric Validation

IsNumeric(string? input)

Determines if string represents a numeric value using double.TryParse.

bool isNum = "123.45".IsNumeric(); // true
bool isNum = "1e10".IsNumeric(); // true (scientific notation)
bool isNum = "abc123".IsNumeric(); // false

String Transformations

Case Conversion

ToTitleCase(string? input)

Converts string to Title Case.

string title = "hello world".ToTitleCase(); // "Hello World"

ToCamelCase(string? input)

Converts string to camelCase.

string camel = "hello world".ToCamelCase(); // "helloWorld"
string camel = "hello_world-test".ToCamelCase(); // "helloWorldTest"

ToPascalCase(string? input)

Converts string to PascalCase.

string pascal = "hello world".ToPascalCase(); // "HelloWorld"

ToKebabCase(string? input)

Converts string to kebab-case.

string kebab = "Hello World".ToKebabCase(); // "hello-world"

ToSnakeCase(string? input)

Converts string to snake_case.

string snake = "Hello World".ToSnakeCase(); // "hello_world"

String Manipulation

Truncation and Padding

Truncate(string? input, int maxLength, string suffix = "...")

Truncates string to specified length with optional suffix.

string short = "Very long text".Truncate(8); // "Very ..."
string custom = "Long text".Truncate(5, "!"); // "Long!"

EllipsisIfTooLong(string? input, int maxLength)

Shorthand for truncation with ellipsis.

string result = "Too long".EllipsisIfTooLong(5); // "To..."

Encoding & Safety

HTML Operations

EscapeHtml(string? input) / UnescapeHtml(string? input)

HTML encoding and decoding.

string escaped = "<script>".EscapeHtml(); // "&lt;script&gt;"
string unescaped = "&lt;test&gt;".UnescapeHtml(); // "<test>"

Base64 Operations

ToBase64(string? input, Encoding? encoding = null)

Encodes string to Base64.

string encoded = "Hello World".ToBase64(); // "SGVsbG8gV29ybGQ="

FromBase64(string? input, Encoding? encoding = null)

Decodes Base64 string.

string decoded = "SGVsbG8gV29ybGQ=".FromBase64(); // "Hello World"

Performance Considerations

  • Most methods use MethodImpl(MethodImplOptions.AggressiveInlining) for performance
  • Uses StringBuilder for string building operations
  • Optimized null checking and early returns
  • Minimal memory allocations in hot paths

Thread Safety

  • All extension methods are thread-safe (stateless)
  • No shared state between method calls
  • Safe for concurrent usage across multiple threads

Best Practices

  1. Choose Appropriate Methods: Use NullIfEmptyOrWhiteSpace() for clean null handling
  2. Performance: Chain operations efficiently with early returns
  3. Validation: Use validation methods for user input processing
  4. Encoding: Always specify encoding for Base64 operations when needed
  5. Case Conversion: Use appropriate case for your specific use case
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