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Writing Custom BizTalk Functoids

, 25 Jan 2006
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An article on how to write custom BizTalk functoids.

Introduction to Functoids

I am sure you have heard about functions, but what about functoids? Functoids or BizTalk functoids are, in a way, small reusable functions that you build just like functions. These are like operations that you need to perform specific tasks on data. BizTalk comes with a good collection of readymade functoids. But you will frequently face situations where you desire a simple functionality. Let us say, you want to validate a credit card number, it will be great if we can build a functoid which can take in a credit card number and credit card type, and return true or false. This will be a very good scenario for writing a functoid of your own.


As a learning exercise, I suggest building a functoid which calculates the perimeter of a rectangle for a fencing company. The logic of the functoid implementation is really concise:

2   x (length + breadth)

A Bird's Eye View of the Steps

To create a BizTalk functoid, we need to briefly do the following:

  • Derive our functoid from Microsoft.BizTalk.BaseFunctoids.
  • Give it all resource strings like function name, function bitmaps to be displayed in the mapper, tool tip text, and description.
  • Give it a unique GUID and a functoid ID.
  • Specify what category the functoid belongs to (Math, Logical, String etc..).
  • Specify input and output parameters.
  • Specify the input and output connection types.
  • Specify the function to call.

Getting Down to Business ..

I have broken down the activity into a series of logical steps.

Step 1: Creating your functoid project

You need to create a functoid as a class library. So we need to select a class library project to begin. Make sure you give a proper namespace name for it as we will need this to load the functoid later, using Reflection. We will use Custom.Biztalk.MathFunctoid as the namespase in our example:

sample screenshot

Step 2: Signing the DLL with a key

You need to have a strong name for this assembly to get it loaded into the toolbox. So create a strong name and sign it:

C:\Samples\MathFunctoid > sn   -k mathFunctoid.snk

Once you have the strong key generated, insert the line below to the AssemblyInfo.cs:

[assembly: AssemblyKeyFile("..\\..\\mathFunctoid.snk")]

Step 3: Give a unique ID for this assembly

We need to give a unique ID for this assembly. Using GUIDGEN from the Visual Studio prompt, generate a new GUID and add the following to the AssemblyInfo.cs:

[assembly: Guid("5DE500CC-45BC-454b-A23D-24449899042C")]

Step 4: Add the class skeleton

We need to have a class to implement this functionality, so add a class and call it CPerimeter (or any meaningful name of your choice):


Once the class is added, add the following lines in the namespace inclusion section at the top of your class file:

using Microsoft.BizTalk.BaseFunctoids; 
using System.Reflection;  
using System.Globalization;  
using System.Resources;

Step 6: Add references to BizTalk base functoids

In the project references, add a reference to Microsoft.BizTalk.BaseFunctoids.dll. This DLL implements all the base classes we need to create a functoid.

Step 7: Add a resource file

In Visual Studio, go to File->Add New Item->Resource File.


I named the resource file Mathresource.resx for this example. Now, add the following resource strings and specify their custom descriptions:

Resource ID Value Explanation
IDS_CONVERTINTFUNCTOID_ID 6123 A value greater than 6000
IDS_FUNCTOID_NAME “Perimeter” The functoid description in toolbox
IDS_MATHFUNCTOID_TOOLTIP “Calculates the perimeter of a rectangle” What appears on the tool tip
IDS_MATH_DESCRIPTION “Calculates the perimeter” Description of functoid in VS
IDS_PERIMETERFUNCTOID_EXCEPTION "Perimeter functoid threw an exception" Description of exception to the Biztalk subsystem

Now, create a 16 x 16 bitmap and add that to the resource file, and reference it as IDS_MATH_BITMAP using the Resource Editor.

Step 8: Implement the class

To implement this class, we derive our class from BaseFunctoid. And in the class, we load the resource file, and set the different parameters like functoid name, tool tip text, and parameters for the functoid.

public class CPerimeter : BaseFunctoid
    static ResourceManager resmgr = new 
    ResourceManager("Custom.Biztalk.MathFunctoid" + 
      ".MathResource", Assembly.GetExecutingAssembly());

    public CPerimeter():base()
        int functoidID;
        functoidID = System.Convert.ToInt32(
        this.ID = functoidID; 

        // This has to be a number greater than 6000
        SetupResourceAssembly("Custom.Biztalk.MathFunctoid" + 
            ".MathResource", Assembly.GetExecutingAssembly());

        //Set Resource strings , bitmaps

        // Minimum and maximum parameters
        // that the  functoid accepts 


        /// Function name that needs to be
        /// called when this Functoid is invoked.
        /// Put this in GAC                    

        //Category for this functoid.
        this.Category = FunctoidCategory.Math;

        //Input and output Connection type
        this.OutputConnectionType = 
             ConnectionType.AllExceptRecord ;

Step 9: Implement the function logic

Now, we implement the functoid logic for the function name specified in the above step, using SetExternalFunctionName. The code below trims the incoming values. This is done because in XML, string data that are numerals could contain white spaces.

public string CalcPerimeter(string RectangleLength, 
                            string RectangleBreadth)
    int ilength = 0;
    int ibreadth = 0;
    int iPerimeter = 0;
    ResourceManager resmgr = new ResourceManager("Custom." + 

    //Remove whitespace
    RectangleLength = RectangleLength.Trim();
    RectangleBreadth = RectangleBreadth.Trim();

    if ( IsNumeric(RectangleLength) && IsNumeric(RectangleBreadth) )
            ilength = Convert.ToInt32(RectangleLength, 
            ibreadth = Convert.ToInt32(RectangleBreadth, 
            iPerimeter = 2  * (ilength + ibreadth);
            throw new Exception(string.Format(resmgr.GetString(
                                RectangleLength +  " "  + 
    return iPerimeter.ToString() ;

Step 10: Compile and Deploy

You are now ready to build and deploy your functoid. Once it is built, copy the Custom.Biztalk.MathFunctoid.dll to Drive:\Program Files\Microsoft BizTalk Server 2004\Developer Tools\Mapper Extensions.

Now, make the DLL available in the GAC, using the following command line operation:

C:\> gacutil /if Copy the Custom.Biztalk.MathFunctoid.dll

Step 11: Adding the functoid to the ToolBox

Open a BizTalk project and go to toolbox, and then right click on the toolbox. Go to Add/Remove items, select the Functoids tab, and browse to Custom.Biztalk.MathFunctoid.dll in the mapper extension folder, and check it.

You should now see your functoid in the toolbox under the list of Mathematical functoids (because we set the category as Math, remember?).

sample image

Step 12: Take a deep breath!

Congrats, you just finished your first custom BizTalk functoid and I am sure it wont be your last!

Points of Interest

Testing the functoid

I have included a small map to test the functoid. You can download this project in the source available for download at the top of this article. It is titled customFunctoid Map.

sample image


You cannot insert a bitmap directly into the resource editor, you will have to use ResEditor to do it. The ResEditor can be found here: C:\Program Files\Microsoft Visual Studio .NET 2003\SDK\v1.1\Samples\Tutorials\resourcesandlocalization\reseditor.


You might get an exception that the functoid was not found.

Exception Caught: Functoid not found: 
  guid({5DE500CC-45BC-454b-A23D-24449899042C})  funcid(6123)

This happens when you GAC the DLL but forget to copy it to the mapper extension folder.


  • Version 1.0 - January 22, 2006.


This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here


About the Author

United States United States
Abhilash is from Kerala, South India. He is presently working as an Integration Consultant for many fortune 500 companies in his current role at Neudesic
Abhilash has been programming since he got his first PC, when they used to load BASIC using tapes. He got his first real PC in 1994 - a 286 with a 40 MB hard disk, 1 MB RAM, and a 5.25 " FDD with a HGA graphics card.
Pascal was his first favorite programming language. And he thought at one time that it was the greatest language. He never really got on to the Delphi wagon, but went with C++, and then progressively VC++ SDK, MFC, COM, and then eventually chose C# as his preferred language once .NET came along. With the emergence of SOA into mainstream, Abhilash chose BizTalk as his SOA realization tool of preference. He opines that BizTalk helps implement SOA; by so clearly separating the message and the underlying implementation, and connect apps purely based on contracts. This is what many classic technologies like IDL tried to do, but somewhere, the point got lost. BizTalk is his tool of choice for EAI. Abhilash has worked in various platforms including Win32,.NET,Linux, and Mainframes and has professional experience in embedded development and voice telephony.This helps him understand the EAI domain better.
His passions include programming, blogging ,cricket and chess. He likes to troll MS user groups and used to run a site as a hobby. The site has a forum, so if you work with BizTalk server, he would like to hear about your experiences there.
He was awarded Biztalk Server MVP in April of 2006.
His life events gets recorded here You can connect with him on Linkedin

Comments and Discussions

QuestionNoob question about custom functoids and XSLT Templates Pinmemberdnieto2318-Apr-12 10:30 
GeneralReg : Custom Functoids Pinmembersiva krishna prasad15-Jun-10 22:15 
QuestionLifetime of a Functoid PinmemberInverso16-Apr-10 22:40 
Generalhi my friends Pinmembereyespi1-Mar-10 2:11 
GeneralBiztalk Custom Functoid Wizard PinmemberLeandroDG15-Sep-09 4:29 
Hello there!
I’ve posted my Biztalk Custom Functoid Wizard in my blog, it’s pretty similar to the Adapter Wizard and Pipeline Component Wizard created by Scott, Boudewijn and Martijn.
I hope everyone can find it of use:
Leandro Díaz Guerra
Lagash Systems S.A.
From Argentina, to the world

GeneralExpecting more deep Article PinmemberMember 35158272-May-08 5:17 
GeneralGood one PinmemberDEEPCHAND_KOSTA28-Jun-07 19:19 
GeneralGUIDGEN PinmemberThunderBiz4-Apr-07 9:12 
GeneralRe: GUIDGEN Pinmember_ABHILASH_MS_7-Jun-07 9:29 
GeneralScript Functoid in External assembly PinmemberNehal9-Feb-07 6:22 
GeneralRe: Script Functoid in External assembly Pinmember_ABHILASH_MS_7-Jun-07 9:28 
GeneralSweet !!! Pinmemberkrazykoder28-May-06 5:42 
GeneralRe: Sweet !!! Pinmember_ABHILASH_MS_29-May-06 7:01 
GeneralI tried this - it works like a dream.... Pinmembervish197913-Feb-06 6:22 
GeneralRe: I tried this - it works like a dream.... Pinmember_ABHILASH_MS_24-Mar-06 21:12 
GeneralNice one Abhilash PinmemberOwner drawn26-Jan-06 20:15 
GeneralRe: Nice one Abhilash Pinmember_ABHILASH_MS_27-Jan-06 8:16 
GeneralNice article Pinmembermalharone26-Jan-06 5:28 
GeneralRe: Nice article Pinmember_ABHILASH_MS_26-Jan-06 6:41 
GeneralRe: Nice article Pinmembermalharone2-Feb-06 13:17 
GeneralHey ! PinmemberMauricio Ritter26-Jan-06 5:08 
GeneralRe: Hey ! PinstaffNishant Sivakumar26-Jan-06 5:36 
GeneralRe: Hey ! PinmemberMauricio Ritter26-Jan-06 6:21 
GeneralRe: Hey ! Pinmember_ABHILASH_MS_26-Jan-06 6:39 
GeneralExcellent article PinmemberBernhard Hofmann25-Jan-06 21:51 

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