String.IsNullOrEmpty Method
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
Indicates whether the specified string is null or an Empty string.
Assembly: mscorlib (in mscorlib.dll)
Parameters
- value
- Type: System.String
The string to test.
Return Value
Type: System.Booleantrue if the value parameter is null or an empty string (""); otherwise, false.
The following code example determines whether each of three strings has a value, is an empty string or is null.
using System; class Example { public static void Demo(System.Windows.Controls.TextBlock outputBlock) { string s1 = "abcd"; string s2 = ""; string s3 = null; outputBlock.Text += String.Format("String s1 {0}.", Test(s1)) + "\n"; outputBlock.Text += String.Format("String s2 {0}.", Test(s2)) + "\n"; outputBlock.Text += String.Format("String s3 {0}.", Test(s3)) + "\n"; } public static String Test(string s) { if (String.IsNullOrEmpty(s)) return "is null or empty"; else return String.Format("(\"{0}\") is not null or empty", s); } } // The example displays the following output: // String s1 ("abcd") is not null or empty. // String s2 is null or empty. // String s3 is null or empty.
Show: