Notes on software and the ideas behind it

Find the meaning
behind the code.

I’m Fred Yang. I write about software—how it works, why it behaves the way it does, and the ideas that make code easier to reason about.

Open the notebook

Working notes / 2026

Recently mapped

Architecture, reactivity, and the hidden relationships that shape frontend systems.

WF

WF runtime engine

The workflow runtime is just a class, you create a instance of the class in your application, make it a static or global, so the instance live through all the live of your application,...
Follow the thread
WF

Get the output from a workflow

The output of the workflow instance is can be obtained by the OutputParameters like the following.
Follow the thread
WF

Debugger WF

To debug a workflow, you need to set the workflow's host project to be the startup project. If this project is class library project, you need to set the default start action, so that...
Follow the thread
WF

Workflow are different

Workflows represent a different programming model. It’s a model that promotes a clear separation between what to do and when to do it. This separation allows you to change the when without affecting the...
Follow the thread
SharePoint

Site column and field type

They are different concept. Site column is higher level concept, and field type are lower level. Site column reference field type. Site column examples are City, Company, FirstName. It can be reused when create...
Follow the thread