How to reference .NET assemblies using PowerShell

Question

I am a C# .NET developer/architect and understand that it uses objects (.NET objects) and not just streams/text.

I would like to be able to use PowerShell to call methods on my .NET (C# library) assembies.

How do I reference an assembly in PowerShell and use the assembly?

Answer 1

With PowerShell 2.0, you can use the built in Cmdlet Add-Type.

You would just need to specify the path to the dll.

Add-Type -Path foo.dll

Also, you can use inline C# or VB.NET with Add-Type. The @" syntax is a HERE string.

C:\PS>$source = @"
    public class BasicTest
    {
        public static int Add(int a, int b)
        {
            return (a + b);
        }

        public int Multiply(int a, int b)
        {
            return (a * b);
        }
    }
    "@

    C:\PS> Add-Type -TypeDefinition $source

    C:\PS> [BasicTest]::Add(4, 3)

    C:\PS> $basicTestObject = New-Object BasicTest 
    C:\PS> $basicTestObject.Multiply(5, 2)

Answer 2

Take a look at the blog post Load a Custom DLL from PowerShell:

Take, for example, a simple math library. It has a static Sum method, and an instance Product method:

namespace MyMathLib
{
    public class Methods
    {
        public Methods()
        {
        }

        public static int Sum(int a, int b)
        {
            return a + b;
        }

        public int Product(int a, int b)
        {
            return a * b;
        }
    }
}

Compile and run in PowerShell:

> [Reflection.Assembly]::LoadFile("c:\temp\MyMathLib.dll")
> [MyMathLib.Methods]::Sum(10, 2)

> $mathInstance = new-object MyMathLib.Methods
> $mathInstance.Product(10, 2)