C# String - Contains() Method

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The C# String Contains() method is used to check whether the specified substring exists within the string using the particular comparison rules. If yes, the method returns a value indicating the occurrence of the specified strings within the main string.

Syntax

Following is the syntax of the C# string Contains() method −

public bool Contains (string value, StringComparison comparisonType);

Parameters

This method accepts the following parameters −

• value: The value to search.
• comparisonType: It is an enumeration value that specifies the rules used in the comparison.

Return value

This method returnstrueif the value parameter is available in the string. If the value is empty, it returns an empty string; otherwise, it returns false.

Example 1: Basic Substring Check

Following is the basic example of the Contains() method which is used to check a substring of a string −

    
using System;
class Program {
   static void Main() {
      string str = "Learning C# with tutorialspoint";
      string substring = "C#";

      bool result = str.Contains(substring);
      Console.WriteLine($"Does the string contain '{substring}'? {result}");
   }
}

Output

Following is the output −

Does the string contain 'C#'? True

Example 2: Case Sensitive Check

Let us look another example of the Contains() method. Here, we check for a case-sensitive string; if it does not match exactly, it returns false −

using System;
class Program {
    static void Main() {
        string str = "Hello, TutorialsPoint";
        string substring = "hello";
        bool result = str.Contains(substring);
        Console.WriteLine($"Case-sensitive check: {result}");
    }
}

Output

Following is the output −

Case-sensitive check: False

Example 3: Case In-Sensitive Check

In this example we use the Contains() method to check for a case-insensitive string; if the string matches whether it is in uppercase or lowercase, it returns true −

using System;
class Program {
   static void Main() {
      string str = "Hello, TutorialsPoint";
      string substring = "hello";
      bool result = str.Contains(substring, StringComparison.OrdinalIgnoreCase);
      Console.WriteLine($"Case-sensitive check: {result}");
   }
}

Output

Following is the output −

Case-sensitive check: True

Example 4: Check with Special Characters

We can also use special characters as a substring to check whether the substring is present in the string using the Contains() method −

using System;
class Program {
   static void Main() {
      string str = "Hello C#";
      string substring = "#";

      bool result = str.Contains(substring);
      Console.WriteLine($"Does the string contain '{substring}'? {result}");
   }
}

Output

Following is the output −

Does the string contain '#'? True