Bits of .NET

✨ More Than Just ${variable}

String interpolation can format numbers, align text, use expressions, and even span multiple lines. Level up your strings.

📝 Formatting Numbers

double price = 1234.5678;
string formatted = $"Price: {price:C2}";        // $1,234.57
formatted = $"Percent: {0.1234:P1}";          // 12.3%
formatted = $"{price:N0}";                    // 1,235
formatted = $"{price:F2}";                    // 1234.57
formatted = $"{price:E4}";                    // 1.2346E+003

// Date formatting
DateTime now = DateTime.Now;
formatted = $"{now:yyyy-MM-dd}";              // 2024-01-15
formatted = $"{now:MMMM dd, yyyy}";           // January 15, 2024
formatted = $"{now:HH:mm:ss}";                // 14:30:45

🎯 Alignment and Expressions

// Right/left alignment
string[] names = ["Alice", "Bob", "Charlie"];
foreach (var name in names) {
  Console.WriteLine($"{name,10}");  // Right-aligned, width 10
  Console.WriteLine($"{name,-10}"); // Left-aligned, width 10
}

// Expressions inside interpolation
int x = 10, y = 20;
string result = $"Sum: {x + y}, Product: {x * y}";

// Ternary operator
bool isAdmin = true;
string role = $"User is {(isAdmin ? "Admin" : "User")}";

// Conditional formatting
double temperature = 25.5;
string weather = $"Temp: {temperature:F1}°C {(temperature > 30 ? "Hot!" : "Nice")}";

// Multi-line strings
string sql = $@"
SELECT * FROM users
WHERE id = {userId}
  AND status = 'active'";

✅ Culture-Specific Formatting

// Invariant culture (for serialization)
string json = $"{{ "price": {price.ToString(CultureInfo.InvariantCulture)} }}";

// Specific culture
var culture = new CultureInfo("de-DE");
string germanPrice = $"Price: {price.ToString("C2", culture)}"; // 1.234,57 €

// Create interpolated string handler for performance
public static void Log(LogLevel level, [InterpolatedStringHandlerArgument("")] ref MyInterpolatedStringHandler handler)
{
    if (IsEnabled(level))
        Console.WriteLine(handler.ToString());
}