Check if two String objects have the same value in C#

To check if two String objects have the same value in C#, you can use several methods. The most common approach is using the Equals() method, which performs a case-sensitive comparison of string values.

Syntax

Following are the main syntax forms for comparing string values −

string1.Equals(string2)
string.Equals(string1, string2)
string1 == string2

Using the Equals() Method

The Equals() method is the recommended way to compare string values. It returns true if both strings have identical content −

Example

using System;

public class Demo {
    public static void Main(String[] args) {
        string str1 = "John";
        string str2 = "John";
        Console.WriteLine("String 1 = " + str1);
        Console.WriteLine("String 2 = " + str2);
        Console.WriteLine("String 1 is equal to String 2: {0}", str1.Equals(str2));
    }
}

The output of the above code is −

String 1 = John
String 2 = John
String 1 is equal to String 2: True

Example with Different Values

using System;

public class Demo {
    public static void Main(String[] args) {
        string str1 = "Tom";
        string str2 = "Kevin";
        Console.WriteLine("String 1 = " + str1);
        Console.WriteLine("String 2 = " + str2);
        Console.WriteLine("String 1 is equal to String 2: {0}", str1.Equals(str2));
    }
}

The output of the above code is −

String 1 = Tom
String 2 = Kevin
String 1 is equal to String 2: False

Case-Insensitive Comparison

For case-insensitive comparison, use the StringComparison.OrdinalIgnoreCase parameter −

Example

using System;

public class Demo {
    public static void Main(String[] args) {
        string str1 = "HELLO";
        string str2 = "hello";
        Console.WriteLine("String 1 = " + str1);
        Console.WriteLine("String 2 = " + str2);
        Console.WriteLine("Case-sensitive comparison: {0}", str1.Equals(str2));
        Console.WriteLine("Case-insensitive comparison: {0}", 
            str1.Equals(str2, StringComparison.OrdinalIgnoreCase));
    }
}

The output of the above code is −

String 1 = HELLO
String 2 = hello
Case-sensitive comparison: False
Case-insensitive comparison: True

Using the == Operator

The == operator also compares string values and behaves similarly to Equals() for strings −

Example

using System;

public class Demo {
    public static void Main(String[] args) {
        string str1 = "Programming";
        string str2 = "Programming";
        string str3 = "Coding";
        
        Console.WriteLine("str1 == str2: {0}", str1 == str2);
        Console.WriteLine("str1 == str3: {0}", str1 == str3);
        Console.WriteLine("Using Equals(): {0}", str1.Equals(str2));
    }
}

The output of the above code is −

str1 == str2: True
str1 == str3: False
Using Equals(): True

Comparison of String Comparison Methods

Conclusion

To compare string values in C#, use the Equals() method for most scenarios. For null-safe comparisons, prefer string.Equals(str1, str2) or the == operator. Use StringComparison.OrdinalIgnoreCase when case-insensitive comparison is needed.