C# Check if String contains Specified Substring

To check if a string str contains specified substring value, or say if specified substring is present in the string, use C# String.Contains(String) method.

Call Contains() method on the string str and pass the substring value as argument. Contains() method returns True if string str contains the substring value.

Examples

1. Check if string contains the substring ‘cd’

In the following program, we take a string in str, and a search string in value, and check if the string str contains the string value as a substring.

C# Program

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using System;
 
class Example {
    static void Main(string[] args) {
        String str = "abcdefgh";
        String value = "cd";
        Boolean result = str.Contains(value);
        Console.WriteLine($"Does string contain specified substring? {result}");
    }
}

Output

Does string contain specified substring? True

2. Check if string contains substring ‘mno’

In this example, we have taken the string value and search string value, such that the search string is not present in the string as a substring.

If substring value is not present in this string str, then Contains() method returns False.

C# Program

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using System;
 
class Example {
    static void Main(string[] args) {
        String str = "abcdefgh";
        String value = "mno";
        Boolean result = str.Contains(value);
        Console.WriteLine($"Does string contain specified substring? {result}");
    }
}

Output

Does string contain specified substring? False

3. Check if string contains substring ‘CD’, ignoring the case

If we would like to ignore case while checking if the substring is present in the string, you may specify to ignore case via StringComparison object as shown in the following example.

C# Program

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using System;
 
class Example {
    static void Main(string[] args) {
        String str = "abcdefgh";
        String value = "CD";
        StringComparison comp = StringComparison.OrdinalIgnoreCase;
        Boolean result = str.Contains(value, comp);
        Console.WriteLine($"Does string contain specified substring? {result}");
    }
}

Output

Does string contain specified substring? True

Conclusion

In this C# Tutorial, we learned how to check if specified substring is present in a given string.