about_Data_Sections

Applies To: Windows PowerShell 2.0

TOPIC
    about_Data_Sections

SHORT DESCRIPTION
    Explains Data sections, which isolate text strings and other read-only
    data from script logic.


LONG DESCRIPTION
    Scripts that are designed for Windows PowerShell can have one or more
    Data sections that contain only data. You can include one or more Data 
    sections in any script, function, or advanced function. The content of
    the Data section is restricted to a specified subset of the Windows
    PowerShell scripting language.

    Separating data from code logic makes it easier to identify and manage 
    both logic and data. It lets you have separate string resource files for 
    text, such as error messages and Help strings. It also isolates the code 
    logic, which facilitates security and validation tests. 

    In Windows PowerShell, the Data section is used to support script
    internationalization. You can use Data sections to make it easier to
    isolate, locate, and process strings that will be translated into many
    user interface (UI) languages. 

    The Data section is a Windows PowerShell 2.0 feature. Scripts with Data
    sections will not run in Windows PowerShell 1.0 without revision.


  Syntax

    The syntax for a Data section is as follows:

        DATA [-supportedCommand <cmdlet-name>] {

            <Permitted content>
        }


    The Data keyword is required. It is not case-sensitive.


    The permitted content is limited to the following elements:

        - All Windows PowerShell operators, except -match   
           
        - If, Else, and ElseIf statements
           
    - The following automatic variables: $PsCulture,  $PsUICulture,  $True,
          $False, and $Null

        - Comments

        - Pipelines

        - Statements separated by semicolons (;)

        - Literals, such as the following:

            a

            1
  
            1,2,3
    
            "Windows PowerShell 2.0"

            @( "red", "green", "blue" )

            @{ a = 0x1; b = "great"; c ="script" }

            [XML] @'
             <p> Hello, World </p>
            '@

        - Cmdlets that are permitted in a Data section. By default, only the 
          ConvertFrom-StringData cmdlet is permitted.

        - Cmdlets that you permit in a Data section by using the 
          SupportedCommand parameter.


    When you use the ConvertFrom-StringData cmdlet in a Data section, you can
    enclose the key/value pairs in single-quoted or double-quoted strings or in 
    single-quoted or double-quoted here-strings. However, strings that contain
    variables and subexpressions must be enclosed in single-quoted strings or
    in single-quoted here-strings so that the variables are not expanded and the
    subexpressions are not executable. 


  SupportedCommand

      The SupportedCommand parameter allows you to indicate that a cmdlet or 
      function generates only data. It is designed to allow users to include 
      cmdlets and functions in a data section that they have written or tested.

      The value of SupportedCommand is a comma-separated list of one or more 
      cmdlet or function names.

      For example, the following data section includes a user-written cmdlet, 
      Format-XML, that formats data in an XML file:

      DATA -supportedCommand Format-XML 
          {    
             Format-XML -strings string1, string2, string3
          }
       


  Using a Data Section

      To use the content of a Data section, assign it to a variable and use
      variable notation to access the content.

      For example, the following data section contains a ConvertFrom-StringData
      command that converts the here-string into a hash table. The hash table
      is assigned to the $TextMsgs variable. 

      The $TextMsgs variable is not part of the data section.
 
          $TextMsgs = DATA {
              ConvertFrom-StringData -stringdata @'
                Text001 = Windows 7
                Text002 = Windows Server 2008 R2
          '@
          }
     
      To access the keys and values in hash table in $TextMsgs, use the
      following commands.

          $TextMsgs.Text001      
          $TextMsgs.Text002



EXAMPLES

    Simple data strings.

        DATA {
            "Thank you for using my Windows PowerShell Organize.pst script."
            "It is provided free of charge to the community."
            "I appreciate your comments and feedback."
        }


    Strings that include permitted variables.

        DATA {
            if ($null) {
           "To get help for this cmdlet, type get-help new-dictionary."
            }
        }   
        

    A single-quoted here-string that uses the ConvertFrom-StringData cmdlet:

        DATA {
          ConvertFrom-StringData -stringdata @'
            Text001 = Windows 7
            Text002 = Windows Server 2008 R2
        '@
        }



    A double-quoted here-string that uses the ConvertFrom-StringData cmdlet:

        DATA  {
          ConvertFrom-StringData -stringdata @"
            Msg1 = To start, press any key.
            Msg2 = To exit, type "quit".
        "@
        }



    A data section that includes a user-written cmdlet that generates data:

    DATA -supportedCommand Format-XML {    
           Format-XML -strings string1, string2, string3
        }


SEE ALSO
    about_Automatic_Variables
    about_Comparison_Operators
    about_Hash_Tables
    about_If
    about_Operators
    about_Quoting_Rules
    about_Script_Internationalization
    ConvertFrom-StringData
    Import-LocalizedData