In C#, String.Contains() is a string method. This method is used to check whether the substring occurs within a given string or not.

It returns the boolean value. If substring exists in string or value is the empty string (“”), then it returns True, otherwise returns False.

Exception − This method can give ArgumentNullException if str is null.

This method performs the case-sensitive checking. The search will always begin from the first character position of the string and continues until the last character position.

Example 1

Contains is case sensitive if the string is found it return true else false

static void Main(string[] args){
   string[] strs = { "Sachin", "India", "Bangalore", "Karnataka", "Delhi" };
   if (strs.Contains("sachin")){
      System.Console.WriteLine("String Present");
   } else {
      System.Console.WriteLine("String Not Present");
   }
   Console.ReadLine();
}

输出

String Not Present

Example 2

static void Main(string[] args){
   string[] strs = { "Sachin", "India", "Bangalore", "Karnataka", "Delhi" };
   if (strs.Contains("Sachin")){
      System.Console.WriteLine("String Present");
   } else {
      System.Console.WriteLine("String Not Present");
   }
   Console.ReadLine();
}

输出

String Present

Example 3

示例 3

static void Main(string[] args){
   string[] strs = { "Sachin", "India", "Bangalore", "Karnataka", "Delhi" };
   var res = strs.Where(x => x == "Sachin").FirstOrDefault();
   System.Console.WriteLine(res);
   Console.ReadLine();
}

输出

Sachin

Example 4

示例4

static void Main(string[] args){
   string[] strs = { "Sachin", "India", "Bangalore", "Karnataka", "Delhi" };
   foreach (var item in strs){
      if (item == "Sachin"){
         System.Console.WriteLine("String is present");
      }
   }
   Console.ReadLine();
}

输出

String is present