Type Conversion & Casting

Syntax

(targetType) value

Examples

int num = 100;
double converted = num;  // implicit: int -> double, safe

Console.WriteLine(converted);  // 100

double price = 19.99;
int wholePrice = (int)price;  // explicit cast required

Console.WriteLine(wholePrice);  // 19 (truncated, not rounded)

string numberText = "42";
int parsed = int.Parse(numberText);
double parsedDouble = double.Parse("3.14");

Console.WriteLine(parsed + 8);        // 50
Console.WriteLine(parsedDouble * 2);   // 6.28

string input = "abc";

if (int.TryParse(input, out int result))
{
    Console.WriteLine($"Parsed: {result}");
}
else
{
    Console.WriteLine($"'{input}' is not a valid number");
}

string text = "123";
int number = Convert.ToInt32(text);
Console.WriteLine(number + 1);  // 124

double d = Convert.ToDouble("3.14");
string backToString = Convert.ToString(number);
Console.WriteLine(backToString + " units");

Best practices

• Use TryParse() instead of Parse() whenever the input might not be valid, to avoid a FormatException crashing your program
• Use explicit casting only when you understand and accept the potential loss of precision from a narrowing conversion
• Prefer int.Parse()/TryParse() over Convert.ToInt32() when you specifically expect a string - Convert is more general-purpose but less precise about intent
• Remember casting a double to an int truncates the decimal part rather than rounding - use Math.Round() first if you want proper rounding

At a glance

Purpose

Applications on the .NET platform

File extension

.cs

Runs in

.NET runtime

Usually used with

.NET SDK and libraries

Specifications & further reading

• C# language reference

Related C# documentation