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...
IsNotNullOrEmpty 如果值为字符串,则可以同时使用静态字符串函数来检查值为$null还是空字符串。 PowerShell if(-not[string]::IsNullOrEmpty($value) ){...} 当我知道值类型应该是字符串时,我经常使用此值。 当我检查 $null 时 我是一个防守脚本手。 每当我调用函数并将其分配给变量时,我检查它是否$null。
<Parameter(Position:=0), ValidateNotNullOrEmpty()> _ Public Property Name() As String() Get Return processNames End Get Set(ByVal value As String()) processNames = value End Set End Property 若要通知 Windows PowerShell 运行时此属性是 Name 参数,System.Management.Automation.Par...
$string="Hello World" The following example checks if a$stringvariable is null or not in PowerShell. It returns the first statement if the variable is not null or empty and the second statement if the variable is null or empty. if($string) {Write-Host"The variable is not null."}else...
如果需要参数有多个值,指定类型为string[] functionTest-MrParameterValidation { [CmdletBinding()]param( [Parameter(Mandatory)] [string[]]$ComputerName) Write-Output$ComputerName} 如果需要指定一个默认参数需要将ValidateNotNullOrEmpty参数验证属性与默认值一起使用,不过不能与必需(Mandatory)参数一起使用!
~/.bash_profile"$content=(Get-Content"$file"-ErrorAction Ignore-Raw)+[System.String]::Empty ...
string to System.Management.Automation.ScriptBlock Cannot use Set-Acl properly despite being file owner and being a member of Administrators Group. Cannot validate argument on parameter 'Name'. The argument is null or empty. Provide an argument that is not null or empty, and then try the ...
添加-NoEmphasize 参数来为 Select-String 输出着色 (#8963)(感谢 @derek-xia!) 重新添加 Get-HotFix cmdlet (#10740) 使Add-Type 可用于托管 PowerShell 的应用程序 (#10587) 在LanguagePrimitives.IsNullLike() 中使用更有效的计算顺序 (#10781)(感谢 @vexx32!) ...
Stringify ErrorRecord with empty exception message to empty string (#24949) (Thanks @MatejKafka!) Add completion single/double quote support for -PSEdition parameter for Get-Module (#24971) (Thanks @ArmaanMcleod!) Error when New-Item -Force is passed an invalid directory name (#24936) (Than...
Passing$nullto any of these functions outputs$null. The only parameter type I haven't found a way to which to pass$nullwithout conversion is[string]; PowerShell always converts$nullto[string]::Empty. PowerShell's behavior in this regard is also inconsistent with C#. The corresponding functio...