自定義PSObject中的額外空間

Question

我正在構建自定義PSObject數組，但我注意到沒有明顯原因正在插入大量額外空間。例如：

PS> $user = @() 
PS> $user += New-Object PSObject -Property @{"Name" = "John Smith"} 
PS> $user += New-Object PSObject -Property @{"Age" = "18"} 
PS> $user += New-Object PSObject -Property @{"City of birth" = "New York"} 
PS> $user += New-Object PSObject -Property @{"Pet" = "none"} 
PS> "[$($user.Name)]" 
[John Smith ] 
PS> "[$($user.Pet)]" 
[ none] 

好像我添加的更多鍵/值對，將更多空間添加到這些值。任何想法，爲什麼這是？

Answer 1

感謝@麥克-Z的評論有關Add-Member。原來這個代碼做我想要的：

PS> $user = New-Object PSObject 
PS> $user | Add-Member -NotePropertyName "Name" -NotePropertyValue "John Smith" 
PS> $user | Add-Member -NotePropertyName "Age" -NotePropertyValue "18" 
PS> $user | Add-Member -NotePropertyName "City of birth" -NotePropertyValue "New York" 
PS> $user | Add-Member -NotePropertyName "Pet" -NotePropertyValue "none" 

Answer 2

$user是一個數組，因此$user.Name的行爲是獲取所有條目的Name屬性。由於它被放入一個字符串中，所以這些值通過空格連接在一起。因此，每次添加條目到$user時，都會在所有屬性的某處添加額外的空間。我不太確定你是否將$user定義爲數組。它會更有意義構建初始化$user爲PSObject的所有屬性和使用的哈希表：

$props = @{ "Name" = "John Smith"; "Age" = "18"; "City of birth" = "New York"; "Pet" = "none"} 
$user = New-Object PSObject -Property $props 

，或者如果你需要動態地建立一些屬性：

$props = @{ "Name" = "John Smith"; "Age" = "18"; "City of birth" = "New York"; "Pet" = "none"} 
if ($myCondition) 
{ 
    $props.PropertyA = "A" 
} 
else 
{ 
    $props.PropertyB = "B" 
} 
$user = New-Object PSObject -Property $props 

，或者如果你是從database it would probably look more like this閱讀他們：

while($reader.Read()) { 
    $props = @{} 
    for($i = 0; $i -lt $reader.FieldCount; $i+=1) { 
     $name = $reader.GetName($i) 
     $value = $reader.item($i) 
     $props.Add($name, $value) 
    } 
    $obj = new-object PSObject -Property $props 
    Write-Output $obj 
}