A good example is a progress bar with a Value set below the Minimum or above the Maximum.
In this case we can coerce the value within the allowed boundaries.
If a local value is available, it reads it directly from the dictionary.
If no value is set if goes up the logical tree and searches for an inherited value.
Obviously we can put code into the setter of the property … WPF will sometimes update the values directly without calling our object code) this will not cover all eventualities. Event handlers are typically removed as part of the Dispose pattern, and then everyone tries really hard to make sure views and other objects get disposed properly.
Introduction Value resolution strategy The magic behind it How to create a Depdency Property Readonly Dependency Properties Attached Dependency Properties Listen to dependency property changes How to clear a local value When you begin to develop appliations with WPF, you will soon stumble across Dependency Properties. NET properties, but the concept behind is much more complex and powerful.
The main difference is, that the value of a normal .
NET property is read directly from a private member in your class, whereas the value of a Dependency Property is resolved dynamically when calling the method that is inherited from Dependency Object. This baseclass defines a key, value dictionary that contains local values of dependency properties.
Thanks thanks for this wonderful tutorial it really helped me a lot to understand Dependency Properties , I just still have a question , I don't understand the fact that the dependency property is declared as static so how comes that every instance has its own value this is the only misundestanding I still have I need your help , thanks in advance .
Thank you a lot :) There is an miistake on Readonly Dependency Properties section.
When you set a value of a dependency property it is not stored in a field of your object, but in a dictionary of keys and values provided by the base class Every time you access a dependency property, it internally resolves the value by following the precedence from high to low. The key of an entry is the key defined with the dependency property. NET property wrapper, it internally calls to access the value.