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

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

asp.net mvc

How Routing Works in asp.net mvc

The mvc stack start with the UrlRoutingModule. The module handle two HttpApplication event.
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asp.net mvc

HttpContextBase.Items

When you using controller, you can easily access HttpContext property, which is not an System.Web.HttpContext, but a HttpContextBase object. This object has a handy Items dictionary, which can allowed you share data over a...
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asp.net mvc

TempData of Controller

TempData is property of Controller. The TempData is used to save the state from page redirected from to the page redirected. So let say, your request is handled by controller1.method1, for some reason, it...
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asp.net mvc

Extension point in asp.net mvc

Extending route. Route matching is first step mvc framework, we can customize how route is matched by adding constraint, and default, and dataToken. We can implement IRouteConstraint. Here is ASP.NET MVC Tip #30 –...
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asp.net mvc

How a view is found

There are some confusing names here. ViewResult is kind of ActionResult. It is return by an object of Controller class. ViewResult uses VewEngineCollection, a collection of IViewEngine, to find a ViewEngineResult. ViewEngineResult may or...
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