In this article we’ll learn about C# I IsNullOrEmpty() Method. This method is named as IsNullOrEmpty() and it is an extension methods of string class. It is used to check whether the given string is null or an Empty. It checks for both i.e null and empty. A string will be null if it has not been assigned a value and it will be empty if it is assigned “” or String.Empty into it.
This method will take a System.String type parameter and will returns a boolean value based upon the input. If it will be null or an empty, then True else False will be returned.
string name = null // initialize it with null value
String.IsNullOrEmpty(name)
//Output will be: True
string name = String.Empty // initialize it with empty value
String.IsNullOrEmpty(name)
//Output will be: True
//you can also check it without above method as(if you want).
if(name!= null || name !="")
{
//perform you action here
} Let’s check it using one example below:
class CodeConfig
{
// create one method to test IsNullOrEmpty method
public static bool checkText(string str)
{
//we used turnery operator below instead of if-else
return (str == null || str == String.Empty) ? true : false;
}
public static void Main(string[] args)
{
//declaring 3 string variables
string v1 = "Code config"; // string with some text
string v2 = ""; //string with empty text
string v3 = null; // string with null in it
bool b1 = checkText(v1);
bool b2 = checkText(v2);
bool b3 = checkText(v3);
// let's check the output now
Console.WriteLine("First string value output= "+ b1);
Console.WriteLine("Second string value output= "+ b2);
Console.WriteLine("Third string value output= "+ b3);
}
}What will be the output, for better understanding try above code yourself in visual studio. You can check more such topics HERE and also do check our Interview Section.