The contains method of String In C#

The string Contains method is used to check whether the specified substring exists in the given string or not and it will return a boolean value.

 

In case, if a substring exists in a string, then the contains method will return true otherwise it will return false.

 

Contains Method Syntax

The following is the syntax for defining a Contains method to check whether the substring exists in a given string or not.

 

public bool Contains(string value)

 From the syntax above, the Contains method will check whether the substring value exists or not and it will return a boolean value.

 Contains Method Example in C#

Following is the example of using Contains() method to check whether the given value (substring) occurs within the string or not.

 

using System;

namespace CsharpnaijaTutorial

{

    class Program

    {

        static void Main(string[] args)

        {

            string msg = "Welcome to Csharpnaija";

            string subtxt = "Csharpnaija";

            Console.WriteLine($"Does {msg} String Contains {subtxt}?: {msg.Contains(subtxt)}");

            string subtxt1 = "csharpnaija";

            Console.WriteLine($"Does {msg} String Contains {subtxt1}?: {msg.Contains(subtxt1)}");

            Console.WriteLine("\nPress Enter Key to Exit..");

            Console.ReadLine();

        }

    }

}

Output of the above code sample is as shown below

 

From the code snippet above, we used a Contains() method to determine whether the given substring value is found in string or not and returning a bool value.

The above output (result) shows that the Contains() method is a case sensitive operation that’s the reason for the “Csharpnaija” substring it returns “true” and for “csharpnaija” substring it returns false.

 Contains Case Insensitive

To perform a case-insensitive string comparison, you need to use the string IndexOf method. Following is an example of performing a case insensitive search in C#.

 

using System;

namespace CsharpnaijaTutorial

{

    class Program

    {

        static void Main(string[] args)

        {

            string msg = "Welcome to Csharpnaija";

            string subtxt = "Csharpnaija";

            Console.WriteLine($"Does {msg} String Contains {subtxt}?: {msg.Contains(subtxt)}");

            string subtxt1 = "csharpnaija";

            StringComparison comp = StringComparison.OrdinalIgnoreCase;

            bool result = msg.IndexOf(subtxt1, comp) > 0 ? true : false;

            Console.WriteLine($"Does {msg} String Contains {subtxt1}?: {result}");

            Console.WriteLine("\nPress Enter Key to Exit..");

            Console.ReadLine();

        }

    }

}

 

The output of the code snippet

From the above example, we used a string IndexOf method to perform a case insensitive search. We will learn more about string IndexOf method in next article.

 From the above result, for both substrings “Csharpnaija” and “csharpnaija” we got a result as true.

 

Thank you