6. Checking for null for String Variables For string values, we can use two more methods i.e.IsNullorEmpty()andIsNullOrWhiteSpace()to check if variable is null. Let’s go through each of them: 6.1 Using IsNullorEmpty() IsNullorEmpty()checks if astring variable is either null or empty. It ...
Checking if a string is NULL or EMPTY is very common requirement in Powershell script. If we don’t do that we will end up with run time errors if we try to perform some operation on that string variable which is empty or null. So the question now is, how to check it? Well, belo...
以下示例中的函数在foreach循环内有一个内联注释。 虽然找到这条注释并不困难,但试想一下,要是这个函数包含数百行代码呢? PowerShell functionTest-MrVerboseOutput{ [CmdletBinding()]param( [ValidateNotNullOrEmpty()] [string[]]$ComputerName=$env:COMPUTERNAME)foreach($Computerin$ComputerName) {#Attempting...
將環境變數設定為 $null 或空字串會從目前的會話中移除。 例如: PowerShell 複製 $Env:Foo = '' $Env:Foo | Get-Member -MemberType Properties Output 複製 Get-Member : You must specify an object for the Get-Member cmdlet. At line:1 char:12 + $env:foo | Get-Member + ~~~ + ...
Check the spelling of the name, or if a path was included, verify that the path is correct and try again. 因為PowerShell 無法辨識 nonsenseString 為Cmdlet 或其他專案,所以會傳回 CommandNotFoundException 錯誤。 特定 trap 語句會設陷這個終止錯誤。 下列文稿範例包含具有相同錯誤的語句 trap: Power...
Testing reveals that the case for an empty string also matches $null. A switch statement cannot distinguish between an empty string and $null. Details Modify the given example like this: $values = '', 5, $null switch ( $values ) { '' { "Value '$_' is an empty string" ; continue...
<UnixDomainSocketEndPoint>] [-Proxy <Uri>] [-ProxyCredential <PSCredential>] [-ProxyUseDefaultCredentials] [-Body <Object>] [-Form <IDictionary>] [-ContentType <String>] [-TransferEncoding <String>] [-InFile <String>] [-OutFile <String>] [-PassThru] [-Resume] [-SkipHttpErrorCheck] [...
如果需要参数有多个值,指定类型为string[] functionTest-MrParameterValidation { [CmdletBinding()]param( [Parameter(Mandatory)] [string[]]$ComputerName) Write-Output$ComputerName} 如果需要指定一个默认参数需要将ValidateNotNullOrEmpty参数验证属性与默认值一起使用,不过不能与必需(Mandatory)参数一起使用!
<UnixDomainSocketEndPoint>] [-Proxy <Uri>] [-ProxyCredential <PSCredential>] [-ProxyUseDefaultCredentials] [-Body <Object>] [-Form <IDictionary>] [-ContentType <String>] [-TransferEncoding <String>] [-InFile <String>] [-OutFile <String>] [-PassThru] [-Resume] [-SkipHttpErrorCheck] [...
<UnixDomainSocketEndPoint>] [-Proxy <Uri>] [-ProxyCredential <PSCredential>] [-ProxyUseDefaultCredentials] [-Body <Object>] [-Form <IDictionary>] [-ContentType <String>] [-TransferEncoding <String>] [-InFile <String>] [-OutFile <String>] [-PassThru] [-Resume] [-SkipHttpErrorCheck] [...