Skip to main content
.NET Framework Class Library
StringIsNullOrEmpty Method

Indicates whether the specified string is or an Empty string.

Namespace:   System
Assembly:  mscorlib (in mscorlib.dll)
Syntax
Public Shared Function IsNullOrEmpty ( _
	value As [%$TOPIC/490acw3e_en-us_VS_110_2_0_0_0_0%] _
) As [%$TOPIC/490acw3e_en-us_VS_110_2_0_0_0_1%]
public static [%$TOPIC/490acw3e_en-us_VS_110_2_0_1_0_0%] IsNullOrEmpty(
	[%$TOPIC/490acw3e_en-us_VS_110_2_0_1_0_1%] value
)
public:
static [%$TOPIC/490acw3e_en-us_VS_110_2_0_2_0_0%] IsNullOrEmpty(
	[%$TOPIC/490acw3e_en-us_VS_110_2_0_2_0_1%]^ value
)
static member IsNullOrEmpty : 
        value:[%$TOPIC/490acw3e_en-us_VS_110_2_0_3_0_0%] -> [%$TOPIC/490acw3e_en-us_VS_110_2_0_3_0_1%]
public static function IsNullOrEmpty(
	value : [%$TOPIC/490acw3e_en-us_VS_110_2_0_4_0_0%]
) : [%$TOPIC/490acw3e_en-us_VS_110_2_0_4_0_1%]

Parameters

value
Type: SystemString

The string to test.

Return Value

Type: SystemBoolean
true if the value parameter is or an empty string (""); otherwise, false.
Remarks

IsNullOrEmpty is a convenience method that enables you to simultaneously test whether a String is or its value is Empty. It is equivalent to the following code:

result = s Is Nothing OrElse s = String.Empty
result = s == null || s == String.Empty;
result = s == nullptr || s == String::Empty;

You can use the IsNullOrWhiteSpace method to test whether a string is , its value is StringEmpty, or it consists only of white-space characters.

Examples

The following example examines three strings and determines whether each string has a value, is an empty string, or is .

Class Sample
   Public Shared Sub Main()
      Dim s1 As String = "abcd" 
      Dim s2 As String = "" 
      Dim s3 As String = Nothing

      Console.WriteLine("String s1 {0}.", Test(s1))
      Console.WriteLine("String s2 {0}.", Test(s2))
      Console.WriteLine("String s3 {0}.", Test(s3))
   End Sub 

   Public Shared Function Test(s As String) As String 
      If String.IsNullOrEmpty(s) Then 
         Return "is null or empty" 
      Else 
         Return String.Format("(""{0}"") is neither null nor empty", s)
      End If 
   End Function  
End Class   
' The example displays the following output: 
'       String s1 ("abcd") is neither null nor empty. 
'       String s2 is null or empty. 
'       String s3 is null or empty.
using System;

class Sample 
{
    public static void Main() 
    {
    string s1 = "abcd";
    string s2 = "";
    string s3 = null;

    Console.WriteLine("String s1 {0}.", Test(s1));
    Console.WriteLine("String s2 {0}.", Test(s2));
    Console.WriteLine("String s3 {0}.", Test(s3));
    }

    public static String Test(string s)
    {
    if (String.IsNullOrEmpty(s)) 
        return "is null or empty";
    else 
        return String.Format("(\"{0}\") is neither null nor empty", s);
    }
}
// The example displays the following output: 
//       String s1 ("abcd") is neither null nor empty.
//       String s2 is null or empty. 
//       String s3 is null or empty.
using namespace System;
String^ Test( String^ s )
{
   if (String::IsNullOrEmpty(s))
      return "is null or empty";
   else 
      return String::Format( "(\"{0}\") is neither null nor empty", s );
}

int main()
{
   String^ s1 = "abcd";
   String^ s2 = "";
   String^ s3 = nullptr;
   Console::WriteLine( "String s1 {0}.", Test( s1 ) );
   Console::WriteLine( "String s2 {0}.", Test( s2 ) );
   Console::WriteLine( "String s3 {0}.", Test( s3 ) );
}
// The example displays the following output: 
//       String s1 ("abcd") is neither null nor empty.
//       String s2 is null or empty. 
//       String s3 is null or empty.
Version Information

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8