本文整理匯總了VB.NET中System.String.IsNullOrEmpty方法的典型用法代碼示例。如果您正苦於以下問題：VB.NET String.IsNullOrEmpty方法的具體用法？VB.NET String.IsNullOrEmpty怎麽用？VB.NET String.IsNullOrEmpty使用的例子？那麽, 這裏精選的方法代碼示例或許可以為您提供幫助。您也可以進一步了解該方法所在類System.String的用法示例。
在下文中一共展示了String.IsNullOrEmpty方法的3個代碼示例，這些例子默認根據受歡迎程度排序。您可以為喜歡或者感覺有用的代碼點讚，您的評價將有助於係統推薦出更棒的VB.NET代碼示例。
示例1: Sample
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輸出：
String s1 ("abcd") is neither null nor empty.
String s2 is null or empty.
String s3 is null or empty.
示例2: Main
Module Example
Public Sub Main()
Dim s As String
Console.WriteLine("The value of the string is '{0}'", s)
Try
Console.WriteLine("String length is {0}", s.Length)
Catch e As NullReferenceException
Console.WriteLine(e.Message)
End Try
End Sub
End Module輸出：
The value of the string is '' Object reference not set to an instance of an object.
示例3: FileSystem
Option Strict On
Imports System.Collections.ObjectModel
Imports System.IO
Public Module FileSystem
Public Sub Main()
Dim dirPath As String = "c:\\"
If String.IsNullOrEmpty(dirPath) Then Exit Sub
If Not Directory.Exists(dirPath) Then Exit Sub
Dim dirs As ReadOnlyCollection(Of String) = My.Computer.FileSystem.GetDirectories(dirPath)
For Each dir As String In dirs
Dim dirInfo As DirectoryInfo = New DirectoryInfo(dir)
Console.WriteLine("{0} : Created {1}", dirinfo.Name,dirInfo.CreationTime)
Next
End Sub
End Module