How to Check if a String Is Null or Empty in C#

1. Check if a String Is Empty or Null in C#
2. Check if a String Is Null in C#
3. Check if a String Variable Is Empty in C#

This tutorial will discuss the methods of checking if a string is empty or null in C#.

Check if a String Is Empty or Null in C#

If we want to check for a string that has either null value or "" value in it, we can use the string.IsNullOrEmpty() method in C#. The string.IsNullOrEmpty() method has a boolean return type. It returns true if the string is either empty or null. See the following code example.

using System;

namespace check_string {
  class Program {
    static void Main(string[] args) {
      string s = null;
      if (string.IsNullOrEmpty(s)) {
        Console.WriteLine("String is either null or empty");
      }
    }
  }
}

Output:

String is either null or empty

In the above code, we assigned the null value to the string variable s and check whether it is empty or null with the string.IsNullOrEmpty() method in C#.

Check if a String Is Null in C#

In the above section, we check for the null value and "" value combined. If we want to separately check whether a string is null or not, we can use the == comparison operator. See the following code example.

using System;

namespace check_string {
  class Program {
    static void Main(string[] args) {
      string s = null;
      if (s == null) {
        Console.WriteLine("String is null");
      }
    }
  }
}

Output:

String is null

In the above code, we check whether the string variable s is null or not with the == comparison operator in C#.

Check if a String Variable Is Empty in C#

As in the previous example, we can also separately check whether a string is empty or not with the string.Empty field in C#. The string.Empty field represents an empty in C#. See the following code example.

using System;

namespace check_string {
  class Program {
    static void Main(string[] args) {
      string s = "";
      if (s == string.Empty) {
        Console.WriteLine("String is empty");
      }
    }
  }
}

Output:

String is empty

In the above code, we check whether the string is empty with the string.Empty field in C#.