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 i
...Java程序检查字符串是否为字母数字 (Java Program to Check String is Alphanumeric or not) java.util.regex.*; class AlphanumericExample...在上面的示例中,我在matches()方法中使用了模式“ [a-zA-Z0-9] +”。 这意味着字符串可以包含介于a到z,A到Z和0到9之间的字符。这里+表示字符串可以包含一...
The variable is not null. Let’s assign an empty string value to a variable and check again. If a variable is not assigned, it also has a null value. $string=""if($string) {Write-Host"The variable is not null."}else{Write-Host"The variable is null." ...
if($value-eq$null) {'The array is $null'}if($value-ne$null) {'The array is not $null'} 如果我未定义$value,则第一个的计算结果为$true,消息为The array is $null。 这里的陷阱是,可以创建一个允许二者都为$false的$value PowerShell ...
if($value-is[string] ) {# do something} 如果您正在使用類別或接受管線上的各種物件,您可以使用這個方法。 您可以將服務或服務名稱作為輸入。 然後檢查您是否有服務,並在只有名稱時擷取服務。 PowerShell if($Service-isnot[System.ServiceProcess.ServiceController] ) {$Service=Get-Service-Name$Service}...
functionTest-MrParameterValidation{ [CmdletBinding()]param( [Parameter(Mandatory)] [string[]]$ComputerName)Write-Output$ComputerName} 如果没有指定ComputerName参数,也许要为其指定一个默认值。 问题是,默认值不能与强制性参数一起使用。 取而代之的是使用带有默认值的ValidateNotNullOrEmpty参数验证属性。
ValueFromPipelineByPropertyName=true )] public string Key { get { return _key; } set { _key = value; } } private string _value = null; /// the value to store [Parameter( Mandatory=true, Position=2, ValueFromPipelineByPropertyName=true )] public string Value { get { return _value;...
[ValidateNotNullorEmpty()] [System.String]$ServerName, [System.String]$DomainName, [System.String]$CARootName, [System.String]$CAServerFQDN, [System.String]$CertSubject, [System.String]$SMBShare, [Parameter(Mandatory=$true)] [ValidateNotNullorEmpty()] [PsCredential]$Credential) Configuration ...
<UnixDomainSocketEndPoint>] [-Proxy <Uri>] [-ProxyCredential <PSCredential>] [-ProxyUseDefaultCredentials] [-Body <Object>] [-Form <IDictionary>] [-ContentType <String>] [-TransferEncoding <String>] [-InFile <String>] [-OutFile <String>] [-PassThru] [-Resume] [-SkipHttpErrorCheck] [...
If you simply remove the[string]type then it will work as expected: function f2 { param ( $x ) return $x } $null -eq (f2 -x $null) There is no value in declaring a parameter as type string because all classes in .Net have to derive from theObjectclass. Therefore every class impl...