How to Compare Strings in C#: Best Practices

Comparing Strings in C#: Techniques, Performance, and Best Practices

By ByteNomads – May 2025

String comparison is one of those deceptively simple tasks in C# that can quickly become complex when you consider culture, case sensitivity, and performance. In this article, we'll explore different methods to compare strings in C#, highlight when to use each one, and look at real-world scenarios — including comparisons for text, numbers as strings, and even enums.

1. Using == and .Equals()

These are the most common methods for comparing strings.

string a = "hello";
string b = "HELLO";

Console.WriteLine(a == b);                 // False (case-sensitive)
Console.WriteLine(a.Equals(b));            // False (also case-sensitive)

When to use:

• When you want a simple, case-sensitive, culture-invariant comparison
• Comparing hard-coded values (e.g., user roles or status)

2. Using String.Equals() with options

string a = "straße";
string b = "STRASSE";

bool result = String.Equals(a, b, StringComparison.OrdinalIgnoreCase);
Console.WriteLine(result);  // False

Why is this important? Because StringComparison.OrdinalIgnoreCase is faster and safer for most technical comparisons (e.g., file names, identifiers).

Common options:

• StringComparison.Ordinal – Fastest, binary comparison
• StringComparison.InvariantCultureIgnoreCase – Case-insensitive, culture-invariant
• StringComparison.CurrentCulture – For UI elements, user input, etc.

3. Using string.Compare()

More flexible than Equals, especially when sorting or ordering is needed.

int result = string.Compare("apple", "Banana", StringComparison.OrdinalIgnoreCase);
Console.WriteLine(result < 0 ? "apple comes first" : "banana comes first");

When to use:

• Sorting strings in a list or UI
• When you need full control over comparison rules

4. Using CultureInfo for Language-Specific Comparison

var turkish = new CultureInfo("tr-TR");
bool same = string.Equals("I", "ı", StringComparison.CurrentCulture);
Console.WriteLine(same); // False in Turkish locale

Culture can dramatically affect string comparison, especially in non-English locales. Be explicit when building globalized apps.

5. Comparing Numbers Stored as Strings

string x = "10";
string y = "2";

Console.WriteLine(x.CompareTo(y));  // Returns 1 (wrong for numeric sort)

This returns incorrect order because it's a lexicographical comparison. Convert to numeric types:

int xNum = int.Parse(x);
int yNum = int.Parse(y);
Console.WriteLine(xNum.CompareTo(yNum)); // Correct

6. Comparing Enums as Strings

enum Status { Pending, Approved, Rejected }

string input = "approved";
bool match = Enum.TryParse(typeof(Status), input, true, out var result);
Console.WriteLine(match); // True

Why it matters:

Enums are often serialized or passed as strings (e.g., API payloads). Use Enum.TryParse with ignoreCase: true for safe matching.

Conclusion

String comparison in C# isn't one-size-fits-all. Choosing the right method — and knowing the cultural and performance implications — helps build more robust and user-friendly applications.

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