I'm looking at sample code here: https://blogs.msdn.microsoft.com/paolos/2010/01/29/how-to-boost-message-transformations-using-the-xslcompiledtransform-class/
But I can't get the helper routine to compile because this statement:
using Microsoft.BizTalk.CAT.Samples.DynamicTransforms.Helpers.Properties;
is giving error:
The type or namespace name 'Properties' does not exist in the namespace 'Microsoft.BizTalk.CAT.Samples.DynamicTransforms.Helpers' (are you missing an assembly reference?)
If I comment that line out, then I get errors on the class "customBTXMessage" (the type or namespace ... cannot be found...)
That sample is for BizTalk 2010.
You should not need to do that for BizTalk 2013 and up, as it already uses XSLT Compiled transform. This actually caused a few problems as per Known issues in BizTalk Server 2013
To run lots of map for testing purposes I would use BizUnit