String.IsNullOrWhiteSpace Method
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
Indicates whether a specified string is Nothing, empty, or consists only of white-space characters.
Assembly: mscorlib (in mscorlib.dll)
Parameters
- value
- Type: System.String
The string to test.
Return Value
Type: System.Booleantrue if the value parameter is Nothing or String.Empty, or if value consists exclusively of white-space characters.
IsNullOrWhiteSpace is a convenience method that is equivalent to the following code, except that it offers superior performance:
White-space characters are defined by the Unicode standard. The IsNullOrWhiteSpace method interprets any character that returns a value of true when it is passed to the Char.IsWhiteSpace method as a white-space character.
The following example creates a string array, and then passes each element of the array to the IsNullOrWhiteSpace method.
Module Example Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock) Dim values() As String = { Nothing, String.Empty, "ABCDE", _ New String(" "c, 20), " " + vbTab + " ", _ New String(ChrW(&h2000), 10) } For Each value As String In values outputBlock.Text &= String.IsNullOrWhiteSpace(value) & vbCrLf Next End Sub End Module ' The example displays the following output: ' True ' True ' False ' True ' True ' True