Run a C# .cs file from a PowerShell Script

I saw no reason why we couldn’t run a .cs file directly from PowerShell, so I took Keith’s snip and added the missing Get-Content parts to do literally what the OP asks for. No need to compile your code, just edit the -Path argument to point to your .cs file.

$source = Get-Content -Path "A:\basic.cs"
Add-Type -TypeDefinition "$source"

# Call a static method
[BasicTest]::Add(4, 3)

# Create an instance and call an instance method
$basicTestObject = New-Object BasicTest
$basicTestObject.Multiply(5, 2)

Basic.cs

public class BasicTest
{
    public static int Add(int a, int b)
    {
        return (a + b);
    }

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