Calculating DP Values

Dependency properties go through an entire sequence of processes to calculate their final value. In most cases, this is one of those WPF things that usually “just works”, but here’s the process in outline, so you’ll understand what happens when you run across something weird:

1 The process begins by determining a base value for the property. The base property itself is calculated from a series of sources. (Keep reading.)

3 The value of a property can be based on an expression, like the value of a field in a data source. (We’ll talk about that in Chapter 22.) An expression takes precedence over the base value.

3 When a value is ANIMATED, its value will change over time. (We’ll talk about animations in Chapter 20.) The animation is applied to the result of Step 2, so it takes precedence over the expression and the base value.