Creating/Working With Nullable Objects in PowerShell - How?

Question

Hi,
how do I create and work with Nullable objects in PowerScript.
None of the tips I found worked:
> ([System.Nullable[System.Int32]]1).GetType().Name
Int32
> ([System.Nullable[System.Int32]]$null).GetType().Name
You can't call a method on a null value expression.
> (New-Object System.Nullable[Int32] 1).GetType().Name
Int32
Any help is appreciated!

Answer 1

Well, nullable: yes, but Nullable: no.
this is what I get in .NET if I call GetType() on a variable of type Nullable[Int32]:
int? a = null; a.GetType();
{Name = "Nullable`1" FullName = "System.Nullable`1[[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]"}
    [System.RuntimeType]: {Name = "Nullable`1" FullName = "System.Nullable`1[[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]"}
    base {System.Reflection.MemberInfo}: {Name = "Nullable`1" FullName = "System.Nullable`1[[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]"}
    Assembly: {mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089}
    AssemblyQualifiedName: "System.Nullable`1[[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]], mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
    Attributes: Public | SequentialLayout | Sealed | Serializable | BeforeFieldInit
    BaseType: {Name = "ValueType" FullName = "System.ValueType"}
    ContainsGenericParameters: false
    DeclaringMethod: "(typeof(int?)).DeclaringMethod" hat eine Ausnahme vom Typ "System.InvalidOperationException" verursacht.
    DeclaringType: null
    FullName: "System.Nullable`1[[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]"
    GenericParameterAttributes: "(typeof(int?)).GenericParameterAttributes" hat eine Ausnahme vom Typ "System.InvalidOperationException" verursacht.
    GenericParameterPosition: "(typeof(int?)).GenericParameterPosition" hat eine Ausnahme vom Typ "System.InvalidOperationException" verursacht.
    GUID: {9a9177c7-cf5f-31ab-8495-96f58ac5df3a}
    HasElementType: false
    IsAbstract: false
    IsAnsiClass: true
    IsArray: false
    IsAutoClass: false
    IsAutoLayout: false
    IsByRef: false
    IsClass: false
    IsCOMObject: false
    IsContextful: false
    IsEnum: false
    IsExplicitLayout: false
    IsGenericParameter: false
    IsGenericType: true
    IsGenericTypeDefinition: false
    IsImport: false
    IsInterface: false
    IsLayoutSequential: true
    IsMarshalByRef: false
    IsNested: false
    IsNestedAssembly: false
    IsNestedFamANDAssem: false
    IsNestedFamily: false
    IsNestedFamORAssem: false
    IsNestedPrivate: false
    IsNestedPublic: false
    IsNotPublic: false
    IsPointer: false
    IsPrimitive: false
    IsPublic: true
    IsSealed: true
    IsSecurityCritical: false
    IsSecuritySafeCritical: false
    IsSecurityTransparent: true
    IsSerializable: true
    IsSpecialName: false
    IsUnicodeClass: false
    IsValueType: true
    IsVisible: true
    MemberType: TypeInfo
    Module: {CommonLanguageRuntimeLibrary}
    Namespace: "System"
    ReflectedType: null
    StructLayoutAttribute: {System.Runtime.InteropServices.StructLayoutAttribute}
    TypeHandle: {System.RuntimeTypeHandle}
    TypeInitializer: null
    UnderlyingSystemType: {Name = "Nullable`1" FullName = "System.Nullable`1[[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]"}
That's quite a difference to PowerShell's:
([System.Nullable[System.Int32]]$null).GetType()
You can't call a method on an expression with value NULL.
See my point? PowerShell apparently doesn't have a notion about Nullable types. That's what I need to find out for myself: "Why?"
Best regards,
Axel Dahmen