This topic is to briefly describe how C# or VB .NET Managed code can be scripted and utilised within a PowerShell script. This topic is not exploring all facets of the Add-Type cmdlet.
For more information on the Add-Type cmdlet, please refer to the MSDN documentation (for 5.1) here: https://msdn.microsoft.com/en-us/powershell/reference/5.1/microsoft.powershell.utility/add-type
|-TypeDefinition<String_>||Accepts the code as a string|
|-Language<String_>||Specifies the Managed Code language.Accepted values: CSharp, CSharpVersion3, CSharpVersion2, VisualBasic, JScript|
In later versions of PowerShell, Remove-TypeData has been added to the PowerShell cmdlet libraries which can allow for removal of a type within a session. For more details on this cmdlet, go here: https://msdn.microsoft.com/en-us/powershell/reference/4.0/microsoft.powershell.utility/remove-typedata
For those experience with .NET it goes without saying that the differing versions of C# can be quite radically different in their level of support for certain syntax.
If utilising Powershell 1.0 and/or -Language CSharp, the managed code will be utilising .NET 2.0 which is lacking in a number of features which C# developers typically use without a second thought these days, such as Generics, Linq and Lambda. On top of this is formal polymorphism, which is handled with defaulted parameters in later versions of C#/.NET.