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
- 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:
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:
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:
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:
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:
|6123||A value greater than 6000 |
|“Perimeter”||The functoid description in toolbox|
|“Calculates the perimeter of a rectangle”||What appears on the tool tip|
|“Calculates the perimeter”||Description of functoid in VS|
|"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
functoidID = System.Convert.ToInt32(
this.ID = functoidID;
this.Category = FunctoidCategory.Math;
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,
int ilength = 0;
int ibreadth = 0;
int iPerimeter = 0;
ResourceManager resmgr = new ResourceManager("Custom." +
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?).
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.
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:
This happens when you GAC the DLL but forget to copy it to the mapper extension folder.
- Version 1.0 - January 22, 2006.