Understanding the difference between String and StringBuilder in .NET

When working with strings in .NET, it's important to differentiate between the String and StringBuilder classes. The key difference lies in how they handle modifications.

String

The String class in .NET is immutable, meaning once a string object is created, it cannot be modified. Every time you perform an operation that alters the string (such as concatenation), a new string object is created in memory. This can lead to inefficiencies when dealing with a large number of modifications.

StringBuilder

On the other hand, the StringBuilder class in .NET is mutable, allowing you to modify the content of the string without creating new string objects. This makes it more efficient when dealing with frequent modifications, especially for operations like string concatenation in loops.

When to use each one?

Use String when you have a static or constant string that does not change frequently. On the other hand, use StringBuilder when you need to modify a string multiple times, particularly in loops or dynamic content generation.

Understanding the differences between String and StringBuilder is crucial for optimizing performance and memory usage in your .NET applications.