📝 String Interpolation = Clean Formatting
String concatenation is messy. String interpolation embeds expressions directly. Readable, concise, elegant.
❌ Concatenation
string msg = "Hello, " + name +
". You are " + age + " years old.
Today is " + date.ToShortDateString();
✅ Interpolation
string msg = $"Hello, {name}.
You are {age} years old.
Today is {date:yyyy-MM-dd}";
📝 Interpolation Examples
// Basic
string name = "Alice";
int age = 30;
string message = $"Hello, {name}! You are {age} years old.";
// Expressions
double price = 99.99;
string result = $"Total: {price * 1.2:C2}"; // Format as currency
// Methods
DateTime now = DateTime.Now;
string date = $"Today is {now.ToLongDateString()}";
// Conditional
bool isActive = true;
string status = $"User is {(isActive ? "active" : "inactive")}";
// Object properties
var user = new User { Name = "Alice", Age = 30 };
string info = $"User: {user.Name}, Age: {user.Age}";
// Formatting
double number = 123.4567;
string formatted = $"Number: {number:F2}"; // 123.46
// Escape braces
string braces = $"{{Escaped}} braces {{}}";
// Verbose (multi-line)
string multiLine = $"
Hello, {name}!
This is a multi-line string.
Today is {DateTime.Now:yyyy-MM-dd}.
";
// With padding
string padded = $"Name: {name,-10} Age: {age,5}";
// Interpolation Benefits
- Clean and readable
- Embed expressions directly
- Formatting support
- Multi-line support
- Better than concatenation
💡 Interpolation Tips
- Use $ prefix for interpolation
- Use @ for multi-line strings
- Use format specifiers for numbers/dates
- Keep expressions simple
- Use verbatim strings for long text
“String interpolation is clean and readable. No more messy concatenation. Essential for C# development.”