PSMDTAG:FAQ: Can I specify a methodname using a variable? e.g. $x.$y()<\/p>\n
PSMDTAG:FAQ: Why do I get METHOD metadata when I specify a method without providing parentheses? <\/p>\n
One of the great things about Windows PowerShell is that it is a latebound language which allows you to do all sorts of incredibly powerful operations. Consider the following code which defines a function to display the properties of an object. The names of the properties come from a file passed into the function:<\/p>\n
PS> function test ($obj, $file) { PS> cat properties.txt PS> test (get-process notepad) properties.txt PS> cat properties2.txt PS> test (get-process notepad) properties2.txt<\/font> This works because you can specify $Obj.$Prop where $prop contains the name of the property you want to see.<\/p>\n So how about Methods? Lets see how that works:<\/p>\n PS> $s=”This is a TEST” It turns out the the parser does not handle this situation. <\/p>\n But now try this:<\/p>\n PS> $s=”This is a TEST” What is happening is that if you specify a METHOD with parens, we call it. If you specify a method without parens, we return the metadata for that method. This can be a tad non-plussing at first but it turns out to be very useful at times. In particular, it allows you to do this:<\/p>\n PS> $s=”This is a TEST” THIS IS A TEST IsPublic IsSerial Name BaseType Enjoy!<\/font><\/font><\/p>\n <\/font><\/font> <\/p>\n Jeffrey Snover [MSFT] PSMDTAG:INTERNAL: Indirectly invoking methods via variable Names<\/font><\/p>\n PSMDTAG:LANGUAGE: Parser does not accept directly support variable substitution for method names<\/font><\/p>\n <\/font><\/p>\n","protected":false},"excerpt":{"rendered":" PSMDTAG:FAQ: Can I specify a methodname using a variable? e.g. $x.$y() PSMDTAG:FAQ: Why do I get METHOD metadata when I specify a method without providing parentheses? One of the great things about Windows PowerShell is that it is a latebound language which allows you to do all sorts of incredibly powerful operations. Consider the following […]<\/p>\n","protected":false},"author":600,"featured_media":13641,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[10,33,34],"class_list":["post-10021","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-powershell","tag-faq","tag-language","tag-methods"],"acf":[],"blog_post_summary":" PSMDTAG:FAQ: Can I specify a methodname using a variable? e.g. $x.$y() PSMDTAG:FAQ: Why do I get METHOD metadata when I specify a method without providing parentheses? One of the great things about Windows PowerShell is that it is a latebound language which allows you to do all sorts of incredibly powerful operations. Consider the following […]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/posts\/10021","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/users\/600"}],"replies":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/comments?post=10021"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/posts\/10021\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/media\/13641"}],"wp:attachment":[{"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/media?parent=10021"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/categories?post=10021"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/powershell\/wp-json\/wp\/v2\/tags?post=10021"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
>> foreach ($prop in cat $file) {“{0,-12} : {1}” -f $prop, $obj.$prop}
>> }
<\/font><\/strong>>><\/font><\/p>\n
<\/font><\/strong>Name
ID<\/font><\/p>\n
<\/font><\/strong>Name : notepad
ID : 456<\/font><\/p>\n
<\/font><\/strong>Name
WS
NPM
Handles<\/font><\/p>\n
Name : notepad
WS : 7483392
NPM : 4520
Handles : 50<\/font><\/p>\n
PS> $method=”ToUpper”
PS> $s.$method()
Unexpected token ‘(‘ in expression or statement.
At line:1 char:12
+ $s.$method() <<<<<\/font><\/p>\n
<\/font><\/strong>PS> $s.ToUpper()<\/font><\/strong>
THIS IS A TEST
PS> $s.ToUpper<\/font><\/strong><\/font>
MemberType : Method
OverloadDefinitions : {System.String ToUpper(), System.String ToUpper(Cultu
reInfo culture)}
TypeNameOfValue : System.Management.Automation.PSMethod
Value : System.String ToUpper(), System.String ToUpper(Cultur
eInfo culture)
Name : ToUpper
IsInstance : True<\/font><\/p>\n
<\/font><\/strong>PS> $s.ToUpper.Invoke()<\/font><\/strong>
THIS IS A TEST
PS> foreach ($method in “ToUpper”,”ToLower”,”GetType”) {$s.$method.Invoke()}<\/font><\/strong><\/font><\/p>\n
this is a test<\/font><\/p>\n
——– ——– —- ——–
True True String System.Object
<\/font><\/p>\n
Windows PowerShell\/Aspen Architect
Visit the Windows PowerShell Team blog at: <\/font>http:\/\/blogs.msdn.com\/PowerShell<\/font><\/a>
Visit the Windows PowerShell ScriptCenter at: <\/font>http:\/\/www.microsoft.com\/technet\/scriptcenter\/hubs\/msh.mspx<\/font><\/a><\/font><\/p>\n