Check whether a string is empty in C#

This article illustrates the different techniques to check whether a string is empty in C#.

We should not use "" or String.Empty to check for empty strings in C#. This causes the string to compare with the empty string by using the Object.Equals() method, and will result in a CA1820 violation. To check for empty strings in C#, you can retrieve the string Length property and compare its value with 0, as illustrated below:

using System;

public class Example

{

public static void Main()

{

string s = string.Empty;

bool isEmpty = s.Length == 0;

Console.WriteLine(isEmpty); // True

}

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The above solution uses string.Empty which doesn’t create any string object in the memory, whereas "" creates a new string object. Another option to check for empty strings in C# is string.IsNullOrEmpty() method. However, this will check the specified string with both null and empty string.

using System;

public class Example

{

public static void Main()

{

string s = string.Empty;

bool IsNullOrEmpty = string.IsNullOrEmpty(s);

Console.WriteLine(IsNullOrEmpty); // True

}

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Note that both Length == 0 comparison and String.IsNullOrEmpty() method performs faster than using Equals() method, which executes remarkably more MSIL instructions.

That’s all about checking whether a string is empty in C#.

Check whether a string is empty in C#

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