how do you pass parameters into string variables in powershell

Question

I am running a command to add machines to the domain and it all works ok.

I now want to take the values in $string1 from parameters values, is there a way of doing this?

$rg = "resourcegroup"
$machines = Get-AzureRmVM -ResourceGroupName $rg

$string1 ='{
  "Name" : "domain.local",
  "User": "domain.local\\domainadmin",
  "Restart" : "true",
  "Options" : "3",
}'

$string2 = '{"Password" : "@@@@@@@@@@@@@B"}'

$machines | ForEach { Set-AzureRmVMExtension -ResourceGroupName $rg
  -ExtensionType "JSONADDomainExtension" -Name "joindomain"
  -Publisher "Microsoft.Compute" -TypeHandlerVersion "1.0" -VMName $_.Name
  -Location "uk west" -SettingString $string1 -ProtectedSettingString $String2 }

Answer 1

Build a custom object and convert it to JSON. That way you stay clear of any and all escaping issues and since the input is actual PowerShell code, it's trivial to change any part of the object:

[pscustomobject] @{
  Name = 'domain.local'
  User = 'domain.local\domainadmin'
  Restart = 'true'
  Options = '3'
} | ConvertTo-Json

yields the following:

{
    "Name":  "domain.local",
    "User":  "domain.local\\domainadmin",
    "Restart":  "true",
    "Options":  "3"
}

Answer 2

The trick appears to be to escape the curly braces by doubling them.

$string1 ='{{
  "Name" : "{0}",
  "User": "{1}",
  "Restart" : "{2}",
  "Options" : "{3}"
}}' -f 'domain.local', 'domain.local\\domainadmin', 'true', '3'

Answer 3

Just concatenate the strings and parameter variables:

param (
    [string]$name
)


$string1 ='{
  "Name" : "' + $name +'",
  "User": "domain.local\\domainadmin",
  "Restart" : "true",
  "Options" : "3",
}'