Always count property as array (JSON convert failure)

PowerShell Help
1

Hi,

I have a problem converting some data to JSON because some objects have array properties while other only have a single property.

Let me try illustrate the problem:

# Object with object-array property inside
$customProp = @()
$customProp += New-Object psobject -Property @{ Name="Test1"; Size="100"}
$customProp += New-Object psobject -Property @{ Name="Test2"; Size="100"}

$object1 = New-Object psobject -Property @{ Name="Object1"; Something="Weird"}
$final1 = $object1 | Select-Object Name, Something, @{n="Custom";e={$customProp}}


# Object with object property inside
$customProp = @()
$customProp += New-Object psobject -Property @{ Name="Test10"; Size="200"}


$object2 = New-Object psobject -Property @{ Name="Object2"; Something="Strange"}
$final2 = $object2 | Select-Object Name, Something, @{n="Custom";e={$customProp}}


$list = @()
$list += $final1
$list += $final2
$list

The output of the above should be:

Name    Something Custom                                            
----    --------- ------                                            
Object1 Weird     {@{Name=Test1; Size=100}, @{Name=Test2; Size=100}}
Object2 Strange   @{Name=Test10; Size=200}

And the problem is showing already here. Object1’s Custom property has and extra set of {} around its content while Object2 is lacking those.
Resulting converting it to JSON:

$list | ConvertTo-Json -Depth 3

[
    {
        "Name":  "Object1",
        "Something":  "Weird",
        "Custom":  {
                       "value":  [
                                     {
                                         "Name":  "Test1",
                                         "Size":  "100"
                                     },
                                     {
                                         "Name":  "Test2",
                                         "Size":  "100"
                                     }
                                 ],
                       "Count":  2
                   }
    },
    {
        "Name":  "Object2",
        "Something":  "Strange",
        "Custom":  {
                       "Name":  "Test10",
                       "Size":  "200"
                   }
    }
]

I really need to have it to be same like this:

[
    {
        "Name":  "Object1",
        "Something":  "Weird",
        "Custom":  [
                                     {
                                         "Name":  "Test1",
                                         "Size":  "100"
                                     },
                                     {
                                         "Name":  "Test2",
                                         "Size":  "100"
                                     }
                                 ]

                   
    },
    {
        "Name":  "Object2",
        "Something":  "Strange",
        "Custom":  [
			{
                       		"Name":  "Test10",
                       		"Size":  "200"
                   	}
		]
    }
]

I need to generate a C# Class from it like this:

public class Custom
{
    public string Name { get; set; }
    public string Size { get; set; }
}

public class RootObject
{
    public string Name { get; set; }
    public string Something { get; set; }
    public List Custom { get; set; }
}

Right now json2charp.com gives me classes like this, which I do not fancy :slight_smile:

public class Value
{
    public string Name { get; set; }
    public string Size { get; set; }
}

public class Custom
{
    public List value { get; set; }
    public int Count { get; set; }
    public string Name { get; set; }
    public string Size { get; set; }
}

public class RootObject
{
    public string Name { get; set; }
    public string Something { get; set; }
    public Custom Custom { get; set; }
}

Any help?

2

I have temporarily overcome this by initializing the $CustomProp array wtih $null ($CustomProp = @($null)) and then do what is necessary with regex afterwards:

-replace ‘“Custom”:{“value”:[null,’, ‘“Custom”:[’ -replace ‘],“Count”:\d},’, ‘],’

If anyone could tell how to do it properly I would still be very glad :slight_smile:

3

There’s a lot going on in the code where you’re initializing your objects. When I changed it to this the JSON output matched what you’re looking for:

$list = @(
    [pscustomobject] @{
        Name = 'Object1'
        Something = 'Weird'
        Custom = @(
            [pscustomobject] @{
                Name = 'Test1'
                Size = '100'
            }

            [pscustomobject] @{
                Name = 'Test2'
                Size = '100'
            }
        )
    }

    [pscustomobject] @{
        Name = 'Object2'
        Something = 'Strange'
        Custom = @(
            [pscustomobject] @{
                Name = 'Test10'
                Size = '200'
            }
        )
    }
)

$list | ConvertTo-Json -Depth 3
4

Figuring out they ‘why’ of your original output is a little trickier. You used the @() operator to force your $customProp variables to be arrays, but then you put those variables into an Expression script block of Select-Object, which will unroll the single-element array. (Which is why you see it as a single object when looking at both $list and the JSON conversion in the original output.)

As for that Value and Count bit in your original output? I have no idea where those are coming from. Could be that you’ve found some bug in the JSON converter, but I’m not seeing it at the moment.

5

Well I’m not sure why exactly you’re doing the Select-Object thing, but if you initialize the objects using the custom property, then it works.

$customProp = @()
$customProp += New-Object psobject -Property @{ Name="Test1"; Size="100"}
$customProp += New-Object psobject -Property @{ Name="Test2"; Size="100"}
$object1 = New-Object psobject -Property @{ Name="Object1"; Something="Weird"; Custom = $customProp }
 
# Object with object property inside
$customProp = @()
$customProp += New-Object psobject -Property @{ Name="Test10"; Size="200"}
$object2 = New-Object psobject -Property @{ Name="Object2"; Something="Strange"; Custom = $customProp }

PS C:\Users\mni> $object1

Custom                                                                                Name                                                                                  Something                                                                            
------                                                                                ----                                                                                  ---------                                                                            
{@{Name=Test1; Size=100}, @{Name=Test2; Size=100}}                                    Object1                                                                               Weird                                                                                


PS C:\Users\mni> $object2

Custom                                                                                Name                                                                                  Something                                                                            
------                                                                                ----                                                                                  ---------                                                                            
{@{Name=Test10; Size=200}}                                                            Object2                                                                               Strange

Edit: And then Dave just ninja-solved the riddle.