如何在PowerShell中扩展JSON中的嵌套数组

我有一个JSON对象数组，如下所示:

[
     {
        "WorkspaceName":  "A",
        "Users":  [
                      {
                          "AccessRight":  "Admin",
                          "UserPrincipalName":  "John"
                      },
                      {
                          "AccessRight":  "Contributor",
                          "UserPrincipalName":  "Jane"
                      }
                  ]
    },
    {
        "WorkspaceName":  "B",
        "Users":  [
                      {
                          "AccessRight":  "Admin",
                          "UserPrincipalName":  "John"
                      }
                  ]
    }
]

我想将这个JSON对象数组输出到CSV文件.具体地说，我希望"扩展"用户数组，使其在单独的行上包括其所有属性，从而在各行中"复制"WorkspaceName属性.因此，我希望CSV文件如下所示:

WorkspaceName   Users_AccessRight   Users_UserPrincipalName
-------------   -----------------   -----------------------
A               Admin               John
A               Contributor         Jane
B               Admin               John

我怎样才能做到这一点？具体地说，如何遍历用户数组中的选定属性？虽然在数组用户中总是有相同的属性，但是每个JSON对象在USERS中可能有不同数量的用户.我try 了以下代码，但它只返回USERS_AccessRight和USERS_UserPrimialName的System.Object[]，并没有像上面所希望的那样"展开"行.

$obj = @"
[
    {
        "WorkspaceName":  "A",
        "Users":  [
                      {
                          "AccessRight":  "Admin",
                          "UserPrincipalName":  "John"
                      },
                      {
                          "AccessRight":  "Contributor",
                          "UserPrincipalName":  "Jane"
                      }
                  ]
    },
    {
        "WorkspaceName":  "B",
        "Users":  [
                      {
                          "AccessRight":  "Admin",
                          "UserPrincipalName":  "John"
                      }
                  ]
    }
]
"@ | ConvertFrom-Json

$pathToOutputFile = "C:\output.csv"

$flattened = $obj | ForEach-Object {
    return [PSCustomObject]@{
        WorkspaceName = $_.WorkspaceName
        Users_AccessRight = $_.Users.AccessRight
        Users_UserPrincipalName = $_.Users.UserPrincipalName
    }
}

$flattened | Export-CSV $pathToOutputFile -NoTypeInformation