方法：

PS C:\Users\Administrator> $aa = @()
PS C:\Users\Administrator> $aa.IsFixedSize

True

PS C:\Users\Administrator>

PS C:\Users\Administrator> $bb = New-Object System.Collections.ArrayList
PS C:\Users\Administrator> $bb.IsFixedSize

False

PS C:\Users\Administrator>

现象：

PS C:\Users\Administrator> $myObject = [PSCustomObject]@{
>>   Name = 'XiaMingliang'
>>   Language = 'PowerShell'
>>   State    = 'Shanghai'
>> }
PS C:\Users\Administrator>
PS C:\Users\Administrator>
PS C:\Users\Administrator> $aa.Add($myObject)
使用“1”个参数调用“Add”时发生异常:“集合的大小是固定的。”
所在位置 行:1 字符: 1
+ $aa.Add($myObject)
+ ~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : NotSupportedException

PS C:\Users\Administrator>
PS C:\Users\Administrator>
PS C:\Users\Administrator> $bb.Add($myObject)
0
PS C:\Users\Administrator>
PS C:\Users\Administrator>
PS C:\Users\Administrator> $bb

Name         Language   State
----         --------   -----
XiaMingliang PowerShell Shanghai


PS C:\Users\Administrator>

继续添加（应用）

PS C:\Users\Administrator> $myObject1 = [PSCustomObject]@{
>>   Name = 'zhangsan'
>>   Language = 'PowerShell'
>>   State    = 'BeiJing'
>> }
PS C:\Users\Administrator>
PS C:\Users\Administrator>
PS C:\Users\Administrator> $bb.Add($myObject1)
1
PS C:\Users\Administrator>
PS C:\Users\Administrator> $bb

Name         Language   State
----         --------   -----
XiaMingliang PowerShell Shanghai
zhangsan     PowerShell BeiJing


PS C:\Users\Administrator> $bb.count
2
PS C:\Users\Administrator>
S C:\Users\Administrator> $bb[0]

Name         Language   State
----         --------   -----
XiaMingliang PowerShell Shanghai


PS C:\Users\Administrator> $bb.GetType()

IsPublic IsSerial Name                                     BaseType
-------- -------- ----                                     --------
True     True     ArrayList                                System.Object


PS C:\Users\Administrator>