How to Overcome Casting Challenges with Generics in WPF Applications?

The challenge of genetic conversion in the type of generic type in WPF applications

In WPF applications, the conversion between generic types is sometimes tricky. A special scene involves converting

types into

type. Generic<派生类型> Generic<基类型> Assuming you have a base WPF UserControl for multiple derivative UserControl. In each derived UserControl code hidden, the event processing program calls the method in the userControl. However, when you try to

type

in the use of DataContext when you try to convert Generic<基类型> in the basis of UserControl. InvalidCastException

The problem is that is a derived type, such as

or DataContext, and the UserControl expects it is an instance of BaseViewModel<线>. BaseViewModel<连接器> Generic<基类型> Core concept understanding

Unfortunately, cannot be converted to

directly. This is a basic limit for generic systems. To explain this, suppose you can execute such a conversion.

Generic<派生类型> Suppose you have a Generic<基类型>, you convert it to

. Then you can try to add a

to . However, this will lead to logic inconsistent, because List<狼> will now include a List<动物>. List<动物> 羊 alternative List<狼> 羊

Although the direct conversion is not feasible, according to your specific needs, there are some possible alternative solutions:

Implementing public interface:

If your derivative types implement a public interface (for example,

), you can convert

to the interface and access public functions in this way.

• Use generic methods in the base class: Define a generic method in the base class, this method accepts appropriate types as parameters. This will allow you to deal with clicks without relying on direct conversion. IBaseViewModel DataContext

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