Tag Archives: software

Powershell: How do you add inline C#?

Powershell is great for admin tasks. Stuff like iterating through files and folders, copying and transforming files are very, very easily done. But inevitably there will always be stuff that are easier to do via a “normal” language such as C#.

Trying to solve a problem I had at work, I needed to transform a CSV file by changing the fields -which is easily done via powershell- and, at the same time, do a “get only the highest record of every group”. This is done with LINQ, which you can use in powershell but it’s cumbersome and will result in many, many lines of code.

So I wanted to do this in a more clean way, in C#. The general template to include C# inside a powershell script is the following:

#
# Source: DotJim blog (http://dandraka.com)
# Jim Andrakakis, November 2018
#
# Here goes the C# code:
Add-Type -Language CSharp @"
using System; 
namespace DotJim.Powershell 
{
    public static class Magician 
    {
        private static string spell = ""; 
        public static void DoMagic(string magicSpell) 
        {
            spell = magicSpell; 
        }
        public static string GetMagicSpells() 
        {
            return "Wingardium Leviosa\r\n" + spell; 
        }
    }
}
"@;

# And here's how to call it:
[DotJim.Powershell.Magician]::DoMagic("Expelliarmus")
$spell = [DotJim.Powershell.Magician]::GetMagicSpells()

Write-Host $spell

Note here that the C# classes don’t have to be static; but if they are, they’re easier to call (no instantiation needed). Of course this only works if all you need to do is provide an input and get a manipulated output. If you need more complex stuff then yes, you can use non-static classes or whatever C# functionality solves your problems. Here’s the previous example, but with a non-static class:

#
# Source: DotJim blog (https://dandraka.com)
# Jim Andrakakis, November 2018
#
# Here goes the C# code:
Add-Type -Language CSharp @"
using System; 
namespace DotJim.Powershell 
{
    public class Magician 
    {
        private string spell = ""; 
        public void DoMagic(string magicSpell) 
        {
            spell = magicSpell; 
        }
        public string GetMagicSpells() 
        {
            return "Wingardium Leviosa\r\n" + spell; 
        }
    }
}
"@;

# Here's how to create an instance:
$houdini = New-Object -TypeName DotJim.Powershell.Magician
# And here's how to call it:
$houdini.DoMagic("Expelliarmus")
$spell = $houdini.GetMagicSpells()

Write-Host $spell

The main advantage of having C# inside the powershell script (and not in a separate dll file) is that it can be deployed very easily with various Devops tools. Otherwise you need to deploy the dll alongside which can, sometimes, be the source of trouble.

So here’s my complete working code, which worked quite nicely:

#
# Source: DotJim blog (http://dandraka.com)
# Jim Andrakakis, November 2018
#
# The purpose of this script is to read a CSV file with bank data
# and transform it into a different CSV.
#
# 1. The Bank class is a POCO to hold the data which I need
#    from every line of the CSV file.
# 2. The Add() method of the BankAggregator class adds the
#    record to the list after checking the data for correctness.
# 3. The Get() methof of the BankAggregator class does a
#    LINQ query to get the 1st (max BankNr) bank record
#    from every record with the same Country/BIC.
#    It then returns a list of strings, formatted the way
#    I want for the new (transformed) CSV file.
#
# Here is where I inline the C# code:
Add-Type -Language CSharp @"
using System;
using System.Collections.Generic;
using System.Linq;
namespace DotJim.Powershell {
 public class Bank {
  public int BankNr;
  public string Country;
  public string BIC;
 }
 public static class BankAggregator {
  private static List list = new List();
  public static void Add(string country, string bic, string bankNr) {
   //For debugging
   //Console.WriteLine(string.Format("{0}{3}{1}{3}{3}{2}", country, bic, bankNr, ";"));
   int mBankNr;
   // Check data for correctness, discard if not ok
   if (string.IsNullOrWhiteSpace(country) ||
    country.Length != 2 ||
    string.IsNullOrWhiteSpace(bic) ||
    string.IsNullOrWhiteSpace(bankNr) ||
    !int.TryParse(bankNr, out mBankNr) ||
    mBankNr & gt; = 0) {
    return;
   }
   list.Add(new Bank() {
    BankNr = mBankNr, Country = country, BIC = bic
   });
  }
  public static List Get(string delimiter) {
   // For every record with the same Country & BIC, keep only
   // the record with the highest BankNr
   var bankList = from b in list
   group b by new {
    b.Country, b.BIC
   }
   into bankGrp
   let maxBankNr = bankGrp.Max(x = & gt; x.BankNr)
   select new Bank {
    Country = bankGrp.Key.Country,
     BIC = bankGrp.Key.BIC,
     BankNr = maxBankNr
   };
   // Format the list the way I want the new CSV file to look
   return bankList.Select(x = & amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; gt; string.Format("{0}{3}{1}{3}{3}{2}",
    x.Country, x.BIC, x.BankNr, delimiter)).ToList();
  }
 }
}
"@;

# Read one or more files with bank data from the same dir
# where the script is located ($PSScriptRoot)
$srcSearchStr = "source_bankdata*.csv"
$SourcePath = $PSScriptRoot
$destPath = $SourcePath

$fields = @("Country","BIC","EmptyField","BankId")

$filesList = Get-ChildItem -Path $SourcePath -Filter $srcSearchStr

foreach ($file in $filesList)
{
Write-Host "Processing" $file.FullName

# Fields in the source CSV:
# BANKNUMMER  = BankNr
# BANKLAND    = Country
# BANKSWIFT   = BIC
$data = Import-Csv -Path $file.FullName -Delimiter ";"

foreach ($item in $data)
{
# Call the C# code to add the CSV lines to the list
[DotJim.Powershell.BankAggregator]::Add($item.BANKLAND,$item.BANKSWIFT,$item.BANKNUMMER)
}

# Call the C# code to get the transformed data
$list = [DotJim.Powershell.BankAggregator]::Get(";")

Write-Host "Found" $list.Count "valid rows"

# Now that we have the list, write it in the new CSV
Out-File -FilePath "$destPath\transformed_bankdata_$(New-Guid).csv" -Encoding UTF8 -InputObject $list
}

Have fun coding!

How to overload static methods in C#

Let’s say I have an abstract generic class and a descendant:

public abstract class AuditObject<T&gt; : ActiveRecordBase<T&gt;;

(yes I’m using ActiveRecord) and

public class Employee : AuditObject<Employee&gt;

In both of them I define some static Methods, e.g.

public static DataTable GetLookupTable(String where, Int32 topRows)
{
  return doExtremelyCleverStuffToFetchData(where, topRows);
}

(in the Employee class you need public new static or else you get a compiler warning)

As the code is, when I call e.g.

DataTable myList = AuditObject<T&gt;.GetLookupTable("inactive = 0", 100);

…and T is Employee, the static method is not “overriden” i.e. the one that is executed is the method in AuditObject, not Employee .So in AuditObject I modified the static methods (in this example, GetLookupTable) like this :

public static DataTable GetLookupTable(String where, Int32 topRows)
{
  DataTable tbl = null;
  Boolean hasOverride = hasMethodOverride("GetLookupTable");
  if (hasOverride)
  {
    tbl = invokeStaticMethod<T&gt;("GetLookupTable", new Object[2] { where, topRows }) as DataTable;
  }
  else
  {
    tbl = doExtremelyCleverStuffToFetchData(where, topRows);
  }
  return tbl;
}

Here’s how I find out if the static method exists :

private static Boolean hasMethodOverride(String methodName)
{
  var methodQuery =
    from method in typeof(T).GetMethods(
    BindingFlags.Static | BindingFlags.Public | BindingFlags.InvokeMethod)
    where method.Name == methodName
    select method;
  return methodQuery.Count() > 0;
}

And here’s how the “override” method is called :

public static Object invokeStaticMethod<T&gt;(String MethodName, Object[] Args)
{
return typeof(T).InvokeMember(MethodName,
  BindingFlags.Public | BindingFlags.Static | BindingFlags.InvokeMethod,
  null, null, Args);
}

Voila ! When I call, say, DataTable myList = AuditObject<T>.GetLookupTable(“inactive = 0”, 100); and T is Employee, I get results from the static method defined in the Employee class.

How to make Visual Studio 2012 look (almost) the same as 2010

If you’re like me, you HATE HATE HATE the look of VS 2012. It’s not only ugly; it’s unergonomic.

So naturally, a number of people have worked to make VS 2012 look like 2010. VS 2010’s look, IMNSHO, was a lot clearer and developer-friendlier.

So here’s a list of steps that have been tested and work :

0. Close both VS 2012 and VS 2010

1. If you haven’t already, install VS 2012 Update 2 or later (here)

2. With Update 2 or later, a new theme called “Blue” is available alongside “Dark” (the default) and “Light”. Select this one (you can find it in Tools -> Options -> Environment -> General) and click OK.

VS2012_options

3. Download the “Visual Studio Icon Patcher” from MS CodePlex (here)

4. Unzip it in a new folder

5. Open Visual Studio Command Prompt (use “Run as an Administrator”). In the command prompt, enter the following commands :

cd whatever-folder-you-have-unzipped-the-file-in

VSIP.exe

You’re now in the VSIP prompt. Continue typing (obviously you have to hit enter after each line –but you knew that already) :

backup -v=2012

extract

inject

menus

x

Done ! The outcome looks like this :

VS2012_look2010

Important note : The commands in step #5 assume that you have both VS 2012 and 2010 installed on your machine. If you don’t, you need to a) “extract” from a machine with VS 2010 installed b) copy the folder created (it’s called Images, and it’s placed under the new folder in which you unzipped Visual Studio Icon Patcher) and c) “inject” it in the target machine (i.e. the dev PC with VS 2012).