C# program to convert string to long

Converting a string to a long data type in C# can be accomplished using several methods. The most common approaches are long.Parse(), Convert.ToInt64(), and long.TryParse() for safe conversion.

Syntax

Following are the different syntaxes for converting string to long −

long result = long.Parse(stringValue);

long result = Convert.ToInt64(stringValue);

bool success = long.TryParse(stringValue, out long result);

Using long.Parse() Method

The long.Parse() method converts a string representation of a number to its 64-bit signed integer equivalent −

using System;

class Demo {
   static void Main() {
      string str = "6987646475767";
      long res = long.Parse(str);
      Console.WriteLine("Original string: " + str);
      Console.WriteLine("Converted to long: " + res);
      Console.WriteLine("Type: " + res.GetType());
   }
}

The output of the above code is −

Original string: 6987646475767
Converted to long: 6987646475767
Type: System.Int64

Using Convert.ToInt64() Method

The Convert.ToInt64() method provides another way to convert a string to long and handles null values gracefully −

using System;

class Demo {
   static void Main() {
      string str1 = "9223372036854775807";  // Max long value
      string str2 = "-9223372036854775808"; // Min long value
      
      long result1 = Convert.ToInt64(str1);
      long result2 = Convert.ToInt64(str2);
      
      Console.WriteLine("Max long value: " + result1);
      Console.WriteLine("Min long value: " + result2);
   }
}

The output of the above code is −

Max long value: 9223372036854775807
Min long value: -9223372036854775808

Using long.TryParse() for Safe Conversion

The long.TryParse() method attempts to convert a string without throwing an exception if the conversion fails −

using System;

class Demo {
   static void Main() {
      string validStr = "123456789";
      string invalidStr = "abc123";
      
      // Safe conversion with TryParse
      if (long.TryParse(validStr, out long result1)) {
         Console.WriteLine("Valid conversion: " + result1);
      }
      
      if (long.TryParse(invalidStr, out long result2)) {
         Console.WriteLine("Valid conversion: " + result2);
      } else {
         Console.WriteLine("Invalid string cannot be converted to long");
      }
   }
}

The output of the above code is −

Valid conversion: 123456789
Invalid string cannot be converted to long

Comparison of Methods

Conclusion

Converting strings to long in C# can be done using long.Parse(), Convert.ToInt64(), or long.TryParse(). Use long.TryParse() when you need safe conversion without exceptions, and long.Parse() when you're certain the string contains a valid number.