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.

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Working notes / 2026

Recently mapped

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

Linq

IEnumberable, IQueryable , Lambda expression - part1

When we type the following code IEnumerable<int> intEnumerable = null; var q1 = intEnumerable.Where( x => x > 10); we know that Where method is not part of the IEnumberable<t> interface or IEnumberable interface,...
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WF

Raise Event from outside

Normally raising event is the responsibility side of a class, but in workflow there is a need to raise event from outside. Here is the code that allow client dynamically raise event externally. class...
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Entity Framework

Disconnected Update with Entity Framework

In the first demo, we get disconnected entity, make change of it, and get copy of original copy from the database, and apply the changed entity to the original entity by using context.ApplyPropertyChanges method,...
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Entity Framework

Reference and EntityKey

When add an entity to your objectContext, if the entity reference an other existing entity, but that entity is not in memory, you need to create a EntityKey like the following.
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Entity Framework

Naming in Entity Framework

When using the entity framework designer, you create you entity model with a naming convention. For example, a table "Customer" will map to a entity type "Customer" and entity set "CustomerSet" . It is...
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