Question

I have

function Foo($a, $b)
{
    $o = @{}
    $o.A = $a
    $o.B = $b
    $post = @{}
    $post.X="x"
    $post.entity =$o
    $newton::SerializeObject($post)
}

then do

foo "a" "b"

I get

Exception calling "SerializeObject" with "1" argument(s): "Self referencing loop detected for property 'Value' with type 'System.Management.Automation.PSParameterizedProperty'. Path 'entity.Members[0]'."

however

function Foo2($o)
{
    $post = @{}
    $post.X="x"
    $post.entity =$o
    $newton::SerializeObject($post)
}

foo2 @{a="a"; b="b"}

works fine. Also

function foo3($a, $b)
{
   $o = @{}
   $o.A = $a
   $o.B = $b
   $newton::SerializeObject($o)
}

foo3 "a" "b"

works but

foo3 "a" 1

fails

The latter can be made to work by doing

 $o.B= [Int32]::Parse($b.Tostring())

Which all seems very odd

powershell v2 on windows 7, json.net 4.4.5

Answer 1

The self referencing loop issue sems to be all about…. the order in which you assign things. The below example works:

function Foo($a, $b)
{
    $o = @{}
    $post = @{}

    $post.entity =$o

    $o.A = $a
    $o.B = $b   

    $post.X="x"

    [Newtonsoft.Json.JsonConvert]::SerializeObject($post)
}

Foo "a" "b"

{"entity":{"A":"a","B":"b"},"X":"x"}

If you convert the type before you pass it in then it will keep your foo3 function generic:

function foo3($a, $b)
{
   $o = @{}
   $o.A = $a
   $o.B = $b
   [Newtonsoft.Json.JsonConvert]::SerializeObject($o)
}


$var2 = [Int32]::Parse((1).Tostring())

Foo3 "a" $var2

{"A":"a","B":1}